Voltase hobby: August 2014

Sunday, August 31, 2014

12 Volt to 32 Volt CT converter DC to DC

Kit that can change the normal 12v dc voltage from a car battery, battery bike 12V motor. With the current 7A. so this circuit is very suitable for power car amplifiers and sound systems that use simple 12V battery.

Transistor checker tool with circuit

The above sequence is a circuit of development of the transistor circuit tester before, which of course added few more components , and resulting in even be better. Examiners transistor circuit above only knows his gain is only on the collector . In addition to well known techniques of data materials used therein . That is , if the elements germanium and the like which are in the tool is still functioning or vice versa.
Part List :
R1=330R/0,5W
R2=27K
R3=1K
R4=1K
R5,R6=5K6
C1=1uF
C2=2,2uF
Q1=Socket transistor
T1=Transformator output (OT)
S1=Switches friction
G1=3V
X1-1,
X1-2=Speaker connector

How to test :
Emitter associated with foot condensator and resistor R4, Base is connected with one leg transformer OT , The Collector is connected to the foot of R2 and R3. If you hear a hiss , the sound in few seconds it still has not changed means that transistor still disqualify technical data.

Build a Single cell Charger Wiring diagram Schematic

This Single cell Charger Circuit Diagram detects a full-charge state and automatically switches to a float condition â€”from 240 mA to 12 mA. The schema uses the 555 timer.

Build a Single cell Charger Circuit Diagram

12V Speed Controller Dimmer

This handy schema can be used as a speed controller for a 12V motor rated up to 5A (continuous) or as a dimmer for a 12V halogen or standard incandescent lamp rated up to 50W. It varies the power to the load (motor or lamp) using pulse width modulation (PWM) at a pulse frequency of around 220Hz. SILICON CHIP has produced a number of DC speed controllers over the years, the most recent being our high-power 24V 40A design featured in the March & April 2008 issues. Another very popular design is our 12V/24V 20A design featured in the June 1997 issue and we have also featured a number of reversible 12V designs.

Project Image :

12V Speed Controller/Dimmer Project Image

For many applications though, most of these designs are over-kill and a much simpler schema will suffice. Which is why we are presenting this basic design which uses a 7555 timer IC, a Mosfet and not much else. Being a simple design, it does not monitor motor back-EMF to provide improved speed regulation and nor does it have any fancy overload protection apart from a fuse. However, it is a very efficient schema and the kit cost is quite low.

Parts layout:

Connection diagram:

There are many applications for this schema which will all be based on 12V motors, fans or lamps. You can use it in cars, boats, and recreational vehicles, in model boats and model railways and so on. Want to control a 12V fan in a car, caravan or computer? This schema will do it for you. The schema uses a 7555 timer (IC1) to generate variable width pulses at about 210Hz. This drives Mosfet Q3 (via transistors Q1 & Q2) to control the speed of a motor or to dim an incandescent lamp.

Circuit diagram :

12V Speed Controller/Dimmer Circuit Diagram

While the schema can dim 12V halogen lamps, we should point out that dimming halogen lamps is very wasteful. In situations where you need dimmable 12V lamps, you will be much better off substituting 12V LED lamps which are now readily available in standard bayonet, miniature Edison screw (MES) and MR16 halogen bases. Not only are these LED replacement lamps much more efficient than halogen lamps, they do not get anywhere near as hot and will also last a great deal longer.

Source : Silicon Chip

Stereo balance indicator

Imagine the scheme stereo balance indicator. It has 3 LEDs showing the predominance of right or left channel, or they are the same level.

Through a chain consisting of C1, VD1, R1 left and C2, VD2, R2 for the right channel signal supplied to the operational amplifier IC1 is enabled by the differential amplifier circuit. The output of IC1 is supplied to a signal noninverting inputs of IC2 and IC3. Will prevail if the right channel outputs IC2 and IC3 will have a high level and lights LD3. Otherwise would prevail if left channel outputs IC2 and IC3 will be low and lights LD1. If the signal levels are the same, the outputs of IC2 and IC3 will have a correspondingly high and low levels, and turns LD2. IC1, IC2, IC3 can apply the type LM358 or 741. Electrolytic capacitors for voltage 16V. LEDs any thin, preferably of different colors. Supply voltage 15-30V.

The whole setup is reduced to install IC2 and IC3 balance by adjusting the R8 and R9.

Original article source cxem.net

Build a Key Operated Gate Locking System Circuit

This simple key-operated gate locking system allows only those persons who know the preset code to open the gate. The code is to be entered from the keypad within the preset time to operate the motor fitted in the gate. If anyone trying to open the gate presses a wrong key in the keypad, the system is disabled and, at the same time, sounds an alarm to alert you of an unauthorized entry.

Figs 1 and 2 show the block and schema diagrams of the key-operated code locking system, respectively. Connect points A, B, C, D, E, F and ground of the schema to the respective points of the keypad. Keys S7, S16, S14 and S3 are used here for code entry, and the remaining keys are used for disabling the system. It is very important to press the keys in that order to form the code. To start the motor of the gate, press switches S7, S16, S14 and S3 sequentially. If the keys are pressed in a different order from the preset order, the system will lock automatically and the motor will not start.

Fig. 1: Block diagram of simple key-operated gate locking system
.

Initially, 6V is not available at pin 14 of AND gate IC6, so no pulse reaches the base of npn transistor T1 to trigger timer IC5 and, as a result, the gate doesn’t open. To enable the system, first you have to trigger IC4. Pressing switch S7 triggers timer IC4 to provide 6V to IC6 for approximately 17 seconds. Within this time, you have to press switches S16, S14 and S3 sequentially. As a result, the outputs of timers IC1, IC2 and IC3 sequentially go high. These high outputs are further given to gates N1 and N2 of IC6 to trigger IC7 via npn transistor T1. The time durations for the high outputs of IC1, IC2 and IC3 are preset at 13.5, 9.43 and 2.42 seconds, respectively.

When all the four switches (S7, S16, S14 and S3) are pressed sequentially, timer IC7 triggers to start the motor for the preset period to open the gate. Once the time elapses, the motor stops automatically. The ‘on’ time for the motor can be selected by adjusting preset VR5. Here, the minimum ‘on’ time is 5.17 seconds and the maximum ‘on’ time is 517 seconds.

If a switch other than S7, S16, S14 and S3 is pressed, IC5 triggers to energise relay RL1, which disconnects the power supply of the second relay and the system gets locked and piezobuzzer PZ1 sounds an alarm to alert you that somebody is trying to open the gate lock.

Now to stop the sound and reset the system again press any key (other than S7, S16, S14 and S3) from the keypad.

Key-Operated Gate Locking System Circuit

The schema works off 6V DC regulated power supply and can be easily assembled on a general-purpose PCB.

Author: Dipanjan Bhattacharjee

Make a Best Tracking Transmitter Wiring diagram Schematic

Make a Best Tracking Transmitter Circuit Diagram. This tracking transmitter consists of four distinct sub assemblies; a free-running multivibrator, a transmit switch, an audio-tone generator, and an FM transmitter. The multivibrator (which produces a pulse width with a pulse separation of 1500 ms) is built around Ql and Q2. The multivibrator output is coupled through R5 to the base of Q3, whose emitter feeds Q4, which controls the schema`s transmitter section.

Best Tracking Transmitter Circuit Diagram

Simple 0V to 50 Volt Variable Regulator

A very simple variable power supply schema can be made using this electronic schema diagram .This variable regulator schema will provide an variable regulated output voltage , between 0 and 50 volts . The CA3140 operational amplifier compares the regulator output to a reference voltage , that depends on the R9 value.

Simple 0V to 50 Volt Variable Regulator Circuit Diagram

The output voltage will be nominally twice the voltage between the positive input ( noninverting ) of the CA3140 and ground . The unregulated input voltage must be around 60 volts The output voltage can be set between 0 an 50 volts using R9 potentiometer .The 2N3055 transistors must be mounted on a heatsink , to prevent the overheating of transistors .

4 x 6W POWER AMPLIFIER FOR CAR RADIO

This is a TDA7372 POWER AMPLIFIER FOR CAR RADIO circuit diagram

Circuit Diagram

4 x 6W POWER AMPLIFIER FOR CAR RADIO

Honda CB125S Motorcycle Electrical Circuit Diagram

This is the electrical circuit diagram of the Honda CB125S motorcycle. This circuit diagram is quite clear to see and read, in a gray-scale mode color.

Honda CB125S Motorcycle Electrical Circuit Diagram

You will see here many parts like: turn signal light, neutral indicator, turn signal indicator light, speedometer light, speedometer, headlight, tachometer, headlight control switch, etc. There are also some abbreviation that refer to the wire color codes.

You can save this image for free, right click on image, choose save image as, choose saving location, and save into your PC. Stay safe and enjoy your work.

12W single ended car radio power amplifier with diagnostic interface

General Description for TDA8565Q:

The TDA8565Q is an integrated class-B output amplifier in a 17-lead DIL-bent-to-SIL power package. It contains 4 × 12 W single-ended amplifiers.

Features of TDA8565Q:

Requires very few external components

High output power

Fixed gain

Diagnostic facility (distortion, short-circuit andtemperature detection)

Good ripple rejection

Mode select switch (operating, mute and standby)

Load dump protection

AC and DC short-circuit safe to ground and to VP

Low power dissipation in any short-circuit condition

Thermally protected

Reverse polarity safe

Electrostatic discharge protection

No switch-on/switch-off plop

Flexible leads

Low thermal resistance

Identical inputs.

Circuit digram for TDA8565Q:

12W single-ended car radio power amplifier with diagnostic interface

Datasheet for TDA8565Q: Download

Where you can buy:Aliexpress

Saturday, August 30, 2014

1995 Ford Probe Wiring Diagram

This is 1995 Ford Probe Wiring Diagram: interior fuse panel, power relay, splice, connector, engine
compartment, fuse box, power distribution, solenoid valve, automatic transaxle, solid state, powertrain ctrl module, fuel pump module, shutoff switch

Simple Crowbar Wiring diagram Schematic

These diagram provide overvoltage protection in case of voltage regulator failure or application of an external voltage. Intended to be used with a supply offering some form of short schema protection, either foldback, current limiting, or a simple fuse. The most likely application is a 5 V logic supply, since TTL is easily damaged by excess voltage.

The values chosen in A are for a 5 V supply, although any supply up to about 25 V can be protected by simply choosing the appropriate zener diode. When the supply voltage exceeds the zener voltage +0 V, the transistor turns on and fires the thyristor. This shorts out the supply, and prevents the voltage rising any further. In the case of a supply with only fuse protection, it is better to connect the thyristor the regulator schema when the crowbar operates.

The thyristor should have a current rating about twice the expected short schema current and a maximum voltage greater than the supply voltage. The schema can be reset by either switching off the supply, or by breaking the thyristor schema with a switch.

Simple Crowbar Circuit Diagram

Schematic Power Amplifier with adjusting voltage

Power amplifier using IC TDA1013 , minimum require voltage 15 volt and maximum voltage 35 volt . But you can adjust supply voltage with potentio meter 10K Ohm . Maximum power output 12 Watt with impedance 4 Ohm.

See schematic power below :

Circuit can be used for :

Tuner
Tape
CD
DVD
MP3,MP4,MP5 Player
PC
etc.

Simple Programmable Amplifier Wiring diagram Schematic

This is a Simple Programmable Amplifier Circuit Diagram, A programmable-gain amplifier (PGA) is an electronic amplifier (typically an operational amplifier) whose gain can be controlled by external digital or analog. Often a schema will be called upon to perform several functions. In these situations, the variable gain configuration of this schema could be quite useful.

Simple Programmable Amplifier Circuit Diagram

This programmable gain stage depends on CMOS analog switches to alter the amount of feedback, and thereby, the gain of the stage. Placement of the switching elements inside the relatively low current area of the feedback loop, minimizes the effects of bias currents and switch resistance on the calculated gain of the stage.

Voltage spikes can occur during the switching process, resulting in temporarily reduced gain because of the make before- break operation of the switches. This gain loss can be minimized by providing a separate voltage divider network for each level of gain.

Subowoofer audio car amplifier

For the a one amplifier circuit is very suitable for use in applications subwoofer speaker, which allows for higher spending enough bass. Although output was spent not high, but for bass sounds do not undoubtedly. Indeed, the output is only 20W mono amplifier with 8 ohm impedance. With a maximum supply 44Volt DC.

TDA1562Q Audio Amplifier 50W

TDA1562Qgeneral description:

Philips designers have further improved a number of properties of the IC, among which the power output. According to the Philips datasheet, the improved device, the TDA1562Q, can deliver 70 watts into 4 ohms, but that is at the cost of the distortion, which at 10 per cent is rather too high, even for in a car. The prototype of the design described in this article provides 54 watts into 4 ohms at 1 per cent distortion. Since the number of requisite external components is smaller than in the case of the earlier device, the printed-circuit board is even more compact than that for the February 1995 amplifier.

TDA1562Q features:

Low power dissipation during reproduction of music signals

Proof against short-circuits

Protection against excessive temperatures

Standby switch

No power-on or power-off clicks

Visible error indication

Measurement results (at Ub=14.4 V)

Supply voltage 8–18 V

Sensitivity 760 mV r.m.s.

Input impedance 70 kΩ

Power output 54 W r.m.s. into 4 Ω (f=1 kHz; THD+N=1%)

Harmonic distortion (THD+) at 1 W into 4 Ω: 0.046% (1 kHz)0.29% 20Hz) at 35 W into 4 Ω: 0.12% (1 kHz) 0.7% (20 kHz)

Signal-to-noise ratio (with 1 W into 4 Ω) 88 dBA

Power bandwidth 7.5 Hz – 185 kHz (at 25 W into 4 Ω)

Quiescent current about 135 mA (‘on’)

TDA1562Q applications:

Television sets
Home-sound sets
Multimedia systems
All mains fed audio systems
Car audio (boosters).

TDA1562Q amplifer diagram:

TDA1562Q pcb:

TDA1562Q part lists:

R1= 1MΩ
R2 = 4kΩ7
R3 = 1kΩ
R4 = 100kΩ
Capacitors:
C1,C2 = 470nF
C3,C4 = 10µF 63V radial
C5,C6,C8 = 4700µF 25V radial
(18mm max. dia., raster 7.5 mm)
C7 = 100nF, raster 5 mm
Semiconductors:
D1 = high-efficiency-LED
IC1 = TDA1562Q (Philips)
Miscellaneous:
S1 = single-pole on/off switch
Four spade connectors, PCB mount
Heatsink for IC1 (Rth<2.5 K/W)
PCB, order code 000004-1 (see Readers Services pages)

Fire Alarm using NE555 and temperature sensor

This is a simple series of fire alarms. In this series used NE555 timer and temperature sensor to detect high temperatures. The working principle of this temperature sensor that is when the temperature is high around the sensor then there is resistance on the sensor to be small.

However if the low temperature then the resistance will be high. If the resistance of small sensors, the voltage supply will be able to flow past the sensor and activate the transistor.

IC1 NE555 as a regulator of the audio frequency. Transistors 1 and 2 are used as a driver IC1. Output (pin 3) of IC1 would trigger a transistor base T3 (SL100), which drives the speaker to produce sound the alarm. Frequency NE555 depending on resistance values of R5 and R6 and the capacitance sensor C2 temperature. When the temperature gets hot, would provide a low resistance so that supply voltage can flow into the base of transistor T1 through a diode D1 and R2.

Capacitor C1 will charge a positive voltage so that it will increase the time when the fire alarm. The greater the value of C1, the greater the positive bias applied to the base of transistor T1 (BC548). T1 collector coupled to the base transistor T2, transistor T2 provides a positive voltage to pin 4 (reset) from IC1 (NE555). Resistors R4 will make IC1 NE555 continued to be active despite no positive voltage flowing.

20W Surround audio amplifier with SI 1020G

Have you been use the IC above? if those who have not, IC above is used or applied to the audio power amplifier. IC processing is quite good for use on amplifier home, or room. IC used is SI1020G who have not very high output with only 20W 8 ohm impedance speakers. Supply voltage ranging from 12 volt to 23 volts.

Below schematic audio amplifier with IC SI1020G

Part List

R1 = 100K

R2 = 1R

C1 = 2u2F

C2 = 100uF
C3 = 47uF

C4 = 10uF
C5 = 2200uF
C6 = 47uF

C7 = 100uF

Solar System and WAPDA Switching System

Solar System and WAPDA Switching System

TL081 Tunable notch filter

This narrow-stop-band filter can be tuned by the pot to place the notch at any frequency from 45 to 90 Hz. It attenuates power-line hum or other unwanted signals by at least 30 dB Because the circuit uses wide-tolerance parts, it is inexpensive to build.

Friday, August 29, 2014

Simple Power Converter Wiring diagram Schematic

This simlpe Power Converter Circuit Diagram consists of an a stable multivibrator driving a push-pull pair of transistors into the transformer primary. The multivibrator frequency should~equal around 1 or 2kHz. For higher de voltages, voltage multipliers on the secondary schema have been used successfully to generate 10 k V from a 40~stage multiplier like the one shown.

Power Converter Circuit Diagram

Motor driver L298 Circuit

DC motor driver with H-Bridge IC L293D

IC H Bridge DC motor driver L298 has two H-Bridge circuit in it, so it can be used to download the drive two DC motors. H Bridge DC motor driver L298 each can deliver currents up to 2A. However, in use, the H Bridge DC motor driver L298 can be used in parallel, so the ability to deliver the H Bridge DC motor driver L298 flow into 4A. The consequences of the installation of H Bridge L298 DC motor driver with the parallel mode, you need 2 pieces Bridge H L298 DC motor driver to control two DC motors using H bridge DC motor driver L298 in parallel mode.

H Bridge Pin IC L298 DC motor driver which is connected in parallel operation mode:

* OUT1 connected to OUT4.

* OUT2 OUT3 linked.

* IN1 is connected to IN4.

* IN2 connected to IN3.

* ENABLE ENABLE A linked to B.

OUT1/OUT4 and OUT2/OUT3 associated with DC motors to be controlled.

Please note that the output of the L298 does not have a safety diode. Thus, the need to add two diodes - flyback diodes, with appropriate current capability, at any point output.

Simple 30 Watt VHF Amplifier by using 2SC1946A

The 30 watt amplifier schematic shown below provides an appropriate power boost with an input of 4 watt up to 6 watts. The schema is designed to cover 88-108MHz FM Broadcast Band. However, the schema is very stable at my place and provides a clean-output through seven (7) element Butter-worth low-pass filter.

Simple 30 Watt VHF Amplifier Circuit Diagram:

Notes:

The heart of the schema is 2SC1946A VHF RF power transistor. The transistor is specifically designed for operation in frequencies up to 175 MHz, with very good results. As you can see, the power line is well decoupled. The amplifier current can be over 5 amps. All the coils are made from 16gauge laminated wire (or Silver copper wire can do best) and the RFC can be of HF toroid core (as shown in the picture) or 6 holes ferrite bead.C3 and R1 forms snubber schema while R2 and C6 prevent the amplifier from self-oscillation at VHF, sometimes you need to add 180 ohms in parallel with L7.That will cause the amplifier to dissipate UNDESIRABLE VHF thereby reducing spurious level.

The photo below is 60Watts VHF power amplifier using the above schema. Two of 2SC1946A transistors are arranged at 90 degrees to each other and their outputs are combined using "Power Combiner Network”. It is quite difficult to combine powers at VHF and UHF bands.

However, I recommend that hobbies should stick to single power design due to its complicity and large rate of INTERFERENCE. (in attempt to go for double transistors which involves power combiner network). Since the two amplifiers are operating in different phase (out of phase).

Tuning:

Tuning of the amplifier is not hard at all. You just have to connect the output to a good antenna with a transmission line (RG214) of 50 ohms. First match the output network, and then do the same to the input network for a maximum power output. By way of adjustment, you can increase the output at its operating frequency.

Solar LED Lantern Wiring diagram Schematic

This solar LED lantern can be used as an emergency light. Its 6V battery can be charged either from 230V, 50Hz AC mains or a 12V, 10W solar panel. Two LED indicators have been provided—red LED (LED1) indicates battery charging and green LED (LED2) indicates fully-charged battery.

Solar LED Lantern Circuit Diagram

You can choose to charge the battery either from the mains power or the solar panel by using the single-pole, double-throw (SPDT) switch. Capacitor C1 (1000µF, 35V) removes ripples from the power supply and regulator IC LM7809 (IC1) provides regulated 9V DC to the emitter of pnp transistor T1 (TIP127/BD140) and pin 7 of op-amp IC CA3140 (IC2), which is configured in comparator mode.

The reference voltage of 6.3V at pin 2 of IC2 is obtained through the combination of resistor R7 (1-kilo-ohm) and zener diode ZD1 (6.3V). The comparator controls charging of the battery. Pin 3 of IC2 is connected to the positive terminal of the battery to be charged through resistor R5. When the battery is fully charged, it stops charging and the green LED (LED2) glows to indicate the full-charge status.

When the battery voltage is low, diode D1 (1N4007) forward-biases and the battery connects (through resistor R3) to the collector of T1 for charging (indicated by the glowing of red LED1). Three high-wattage white LEDs (LED3 through LED5), such as KLHP3433 from Kwality Photonics, are used for lighting. These are switched on using switch S3.

5 Volt Switching Regulator Power Supply

The switching regulator power supply used LM2575-5.0 on this schematic. You can make the stable voltage by using the 3 terminal regulator like LM317. However, because the output electric current and the inputted electric current are the same approximately, the difference between the input electric power (The input voltage x The input electric current) and the output power (The output voltage x The output current) is consumed as the heat with the regulator. Because it is, the efficiency isn�t good.

Main function of TV tuner

The main function of the tuner is to select the RF signals from the desired frequency spectrum wave on VHF and UHF and more signs in the air Changing RF variable into a fixed IF frequency and to provide sufficient strengthening to cover the original data that has been transmitted.

Block diagram of a series of TV tuner to receive the frequency VHF / UHF

Operational Tuner [Theoretical]

Tuner is controlled by a microprocessor in the TV chassis, which functions to receive / select a frequency. Exchange of information is channeled through the terminal Address, Clock and Data.

In the tuner, there are ICs that function to translate the instruction / data so that the tuner can function to select the desired frequency. The IC consists of some combination of series, including PLL, Local Oscillator [VCO], Mixer and IF amplifier. Everything artifacts in one chip / one chip. For further analysis, CXA3135 IC with I2C format will be taken as an example.

Build a 15V 1 a Regulated Power Supply Wiring diagram Schematic

Build a +15V 1 a Regulated Power Supply Circuit Diagram. This is a simple +15-V-1-a-regulated-power-supply schema diagram. The supply receives + 20 Vdc from the rectifier/filter section. This is applied to pins 11 and 12 of the uA723, as well as to the collector of the 2N3055 series-pass transistor. The output voltage is sampled through R1 and R2, providing about 7 V with respect to ground at pin 4.

+15V 1 a Regulated Power Supply Circuit Diagram

The reference terminal at pin 6 is tied directly to pin 5, the non inverting input of the error amplifier. For fine trimming the output voltage, a potentiometer can be installed between R1 and R2. A 100-pF capacitor from pin 13 to pin 4 furnishes gain compensation for the amplifier. Base drive to the 2N3055 pass transistors furnished by pin 10 of the uA 723. Since the desired output of the supply is 1 A. maximum current limit is set to 1.5 A by resistor Rsc whose value is 0.433 0. A 100-J

1 Ma Current Sink Wiring diagram Schematic

This is the simple 1-Ma Current Sink Circuit Diagram. A fixed current flows through any load that is connected between the positive supply and Ql`s collector. The non inverting terminal of the op amp is grounded, and negative feedback flows between the output of the schema (Ql`s emitter) and the inverting terminal. The voltage across Rl is thus equal to the voltage at the inverting terminal (approximately 0.55 V), so a fixed current of about 1 mA flows through the load, Ql`s emitter, and Rl.

1-Ma Current Sink Circuit Diagram

Power Supply Circuit 11 8V 12V

I was a fan and an Electronics Technician. Almost all electronic devices use Power Supply. If you want to know more about the Power Supply Circuit Diagram Basic, you can browse the articles in this blog. Here I am trying to write an article about the Power Supply.

Lets see Power Supply Circuit 11.8V(12 V) below. Electronic equipment typically uses direct current (DC) and the voltage and current of the adjustable electrical equipment condition. In the picture, shown Schematic Circuit Power Supply 11.8V(12V) is comprised of a transformer is used to reduce the voltage of 220V at the primary and 11.8 V(12V) on the secondary.
You can add N type Transistor MJ 2955 with same paralel connection for the best power output.

Power Supply Circuit 11.8V(12 V)

Simple 8 Watt Audio Power Amplifier Schematic

Here is the schematic for an 8 watt audio power amplifier. This amp can be used as a simple booster, the heart of a more complicated amplifier or used as a guitar amp. It is very small and portable unit and can be powered through 12V battery. I built the schema on a Vero Board and had to add extra inductors, capacitors and resistors to prevent oscillation.

8 Watt Audio Power Amplifier Schematic

8 Watt Audio Power Amplifier Circuit Diagram

Parts:

R1 = 47K
R2 = 2.2R/1W
R3 = 220R/1W
R4 = 2.2R/1W
C1 = 100nF-63V
C2 = 10uF-25V
C3 = 470uF-25V
C4 = 2000uF-25V
C5 = 100nF-63V
IC1 = LM383
SPKR = 4ohm/8W

Notes:

IC1 must be installed on a heat sink.
C1 is for filtering and to prevent oscillation and should not be omitted.
The schema can be built on a Vero Board, universal solder board or PC board, the PC board is preferred.
The schema draws about 880Ma at 12 V.
By swapping the values of R2 and R3; you can turn this amplifier into a guitar amp with no preamp required.
If you cant find 2000uF, then replace C4 with a 2200uF unit.
If you add a 0.2uF capacitor in series with a 1 ohm resistor to the output you can prevent oscillation of the schema under certain conditions.

50W Class B power amplifier circuit

Power amplifier Class-B is the most popular operating modes, and possibly more than 99% of the current series of power amplifier designed and manufactered are of this class. Defining the Class-B is the amount of bias voltage that causes conduction of both output devices to overlap with the current and thus produce the minimum amount possible crossover distrosi.

This Class-B power amplifier performance :
Power Output________________________50W
RL Impedance_______________________8R
Distortion__________________________Below 0.0006% at 1 kHz and 50W/8R
Slew rate___________________________Approximately 35V/us
Noise______________________________-91dBu at the output
EIN_______________________________-117dBu (referred to input)
Frequency response__________________+0, -0.5dB over 20Hz-20kHz

Part List :

Resistor
R1,R8____________________________10K
R2,R3,R13________________________100R
R4_______________________________150R
R5,R10___________________________1K
R6,R7____________________________68R
R9_______________________________500R
R11______________________________220R
R12,R24__________________________100R
R14______________________________18R
R16,R17__________________________0.1R 5W
R18______________________________10R 5W
PR1______________________________1K trim

Capacitor
C1_______________________________10uF
C2_______________________________220uF
C3_______________________________100pF
C4_______________________________4u7F
C5_______________________________1uF
C6_______________________________100nF 400V
C7_______________________________15pF
C7,C8____________________________100nF
C8,C10___________________________220uf

Diode
D1_______________________________1N4148

Transistor
Tr1,Tr3,TR5,TR14__________________MPSA56
Tr4,Tr10,Tr13______________________MPSA06
Tr6_______________________________MJE340
Tr7_______________________________MJ802
Tr8_______________________________MJE350
Tr9_______________________________MJ4502

Regulated 12 Volt Power Supply

A basic regulated 12 Volt power supply. Regulated 12 Volt Power Supply Circuit diagram : Note :

This schema above uses a 13 volt zener diode, D2 which provides the voltage regulation. Aprroximately 0.7 Volts are dropped across the transistors b-e junction, leaving a higher current 12.3 Volt output supply. This schema can supply loads of up to 500 mA. This schema is also known as an amplified zener schema.

High Current Step Up Converter Using MAX641

High Current Step-Up Converter Using MAX641 integrated schema, manufactured by Maxim IC, can be designed a very simple step-up converter using few electronic components. This step-up high voltage converter electronic projects allows a maximum output current up to 1A.

High Current Step-Up Converter Circuit Diagram

Low battery voltage detector input compare LB1 with internal reference of 1.31 V. LBO output goes in low state when the voltage at pin 1 falls below 1.31 V. The threshold voltage for "low battery", is determined by voltage divider R1-R2.

LED D1 illuminates the LBO output when the input voltage falls below 2.62 V.
Input voltage must remain below 5 V. The maximum effectiveness is 80% conversion.

8W AMPLIFIER WITH MUTING

Features:

WIDE SUPPLY VOLTAGE RANGE
8W @ VS=26V, RL = 8Ω, THD=10%
MUTE FACILITY (POP FREE) WITH LOW
CONSUMPTION
AC SHORT CIRCUIT PROTECTION
THERMAL OVERLOAD PROTECTION
(150°C)

DESCRIPTION

The TDA7253 is class AB audio power amplifier assembled in the new Clipwatt package.

Circuit Diagram:

Circuit Diagram for 8W AMPLIFIER WITH MUTING

TransistorAmp software

TransistorAmp software for the design of transistor amplifiers .In this article I will try to gather a list with all the transistor amplifier design software that are free and educational. As you know, you can make the difference by sharing the links to missing resources from this list. With your help the list will grow larger and other electronics enthusiast and amateurs will find the tools to understand, design faster and better a transistor amplifier circuits that will work.

TransistorAmp is freeware and it helps design your individual transistor amplifier quick and easy. With TransistorAmp you are able to create your individual transistor amplifier with a few mouse clicks. TransistorAmp is a program for Microsoft Windows and runs under Windows 2000, Windows XP, Windows Vista and Windows 7.

Download Here
source: http://en.transistoramp.de/

Thursday, August 28, 2014

Wireless Baby Monitor

Walkie-talkies (also known as handheld or PMR, Personal Mobile Radio) can be bought at low prices even from department stores, and they can be operated without a licence in many countries. Considering the low cost, such a set would be very suitable for use as a wireless baby monitor, with the addition of several external components. These are connected to the jack sockets for an external loudspeaker/microphone and an external PTT (Push-To-Talk) switch, which are often found on these devices.

Wireless Baby Monitor Project Image

The walkie-talkie with the extra electronics and microphone is placed in the baby’s room. When the PTT switch on the other walkie-talkie is actuated for about a second the ‘baby’ walkie-talkie produces a series of tones, which the external electronics can detect. This then activates its own PTT switch for about 5 seconds, so it switches over to transmit. During this time the other device can hear what the external microphone picks up.

Figure 1-Wireless Baby Monitor Circuit Diagram

Figure 1 shows the schema that the author designed for this. It has been designed specifically for a Tevion 3000 PMR sold some time ago by Aldi. This type of PMR has a combined jack socket that includes all the required connections.

The voltage present on the PTT connector is used to generate the supply voltage for the schema via R3, D1 and C1/C2. When the loud-speaker output presents a series of tones (when the PTT switch on the other walkie-talkie is held down), it causes T1 to conduct. This also turns on T2 and T3, so that the external microphone is connected to ground. The resulting current that f lows through the microphone should be sufficient to activate the PTT schema in the walkie-talkie, causing it to transmit. If the external microphone doesn’t draw sufficient current, a resistor (R8) should be connected in parallel. Some experimentation with the value of this resistor may be required. If you want to make use of the internal microphone then R8 should be replaced with a wire link.

Figure 2-Wireless Baby Monitor Circuit Diagram

When the walkie-talkie switches to transmit the built-in amplifier stops producing a signal and T1 turns off. However, since electrolytic capacitor C3 has been charged up in the mean time, transistors T2 and T3 will keep conducting for several seconds until C3 has been almost discharged via R4. In the Elektor labs a simpler version with the same functionality (Figure 2) has been designed for use with a cheaper PMR set that can be obtained from Conrad Electronics (PMR Pocket Comm Active Pair, order number 930444). These walkie-talkies have separate jack sockets for the LS/Mic and PTT connections.

When there is a call a series of tones is produced that is used to turn on T1 via R3. T1 then activates the PTT function and the microphone amplifier is turned on. How-ever, it ’s not just the audio signal that is used, but also the DC offset produced when the internal output stage is turned on. Both the internal as well as external loudspeaker are driven via an output capacitor of 100 µF. When there is a call it charges up via R3 and the base-emitter junction of T1. If the walkie-talkie is called often there would be a danger that the output capacitor would remain charged and the DC offset of the audio signal would no longer be sufficient to turn on T1. To prevent this, D1 is connected in reverse across the base-emitter junction of T1, pro-viding a discharge path for the output capacitor.

To keep the schema active for a minimum amount of time the microphone voltage is used to provide an extra base current. This is done by charging C1 via R1. When the transmitter is turned off the microphone and R2/ D1 provide a discharge path for the capacitor. C2 ensures that the schema won’t react to spikes caused by interference. As can be seen from the second schema diagram, use is made of two connectors, a 2.5 mm jack plug for an external headset and a 3.5 mm plug for the PTT function. These connectors are particular to the walkie-talkies we used here. With other types of walkie-talkie you should first check the connection details of the connectors before you connect the schema up.

When the schema is used as a baby monitor you should check that the microphone you’re using can pick up all the sounds. In our case the microphone didn’t appear to be very sensitive. The microphone amplifier has probably been designed for a voice that is near the PMR unit. When used as a baby monitor the microphone should therefore be positioned as close to the baby as possible.

Author : Wolfgang Papke - Ton Giesberts

Universal Laptop Power Supply AC DC Adapter

One of the things you may not think about when buying a new laptop is what will happen if you lose your laptop AC adapters. Sure this does not seem like something you would lose, but it is very easy to misplace. So it is always a good idea to know where to buy another one, or even have another one handy just in case something like this should ever happen.

If you are going to buy laptop AC adapters online you need to make sure it is the right one. The one that comes with the computer is, of course, the best one to have for it, however, if you buy one online just make sure it is going to fit your computer.

Also, be sure that it is a good model of laptop AC adapters. Some of them can get too hot and overheat. The best thing to do is read some online reviews of the notebook battery chargers, and see which ones work the best. From there you can choose the one that you are going to need. I think it is always a good idea to have a back up anyway. Nothing is worse than having a laptop and not being able to use it. So do not let that happen to you. Go out and get an extra one today.

Replacing notebook power supplies is sometimes an expensive process as it the purchase of an air/auto power supply for your laptop. However for those users who need a new power supply for their notebooks or for users planning to travel, Targus have available a Universal adapter series called the Universal 70 Watt AC/DC Power Adapter that gives the user a variety of ways to power their notebooks.

Features

Power on the go, anywhere: Works at home, office, car, boat, or aeroplane.
Lightweight design: At just 213g, this adaptor is lightweight, compact and ideal for travel.
Compatible with other mobile devices: With the optional Targus Accessory Powering System and device tips, you can power your mobile phone or PDA as well as your notebook.

Basically the Universal 70 Watt AC/DC Power Adapter allows you to plug your laptop into a car cigarette lighter, an aero plane power seat system or into the mains to give your notebook the electricity needed to run the unit. Best of all, the device is 98% compatible with popular 70W notebooks and covers a whopping 6,300 models.Visit Tagus Website

Technical Specifications

Compatibility: Airline Compatibility Chart Always call your airline to confirm inflight power seat system and Targus auto/air compatibility.
Varied models of Acer, Apple, Compaq/HP, Dell, Fujitsu, IBM, Panasonic, Sony and Toshiba.
Other: Includes9 tips 91cm AC input cord 91cm DC input cord 1.82m DC output cord User guide.
Size: 13.7 x 5.5 x 2.2 cm.
Technical: 100-230 VAC 11.75-16.00 VDC.
Warranty: Limited Two Year Warranty.
Weight: 213g

Targus Universal 70 Watt AC/DC Power Adapter is a must have device for those notebook users who travel or even for users that need a second power supply for their PC. The unit is relatively quite small and does not weigh much which is perfect for users on the go.