Voltase hobby: controller

Thursday, September 4, 2014

Simple Train And Slot Car Controller Wiring diagram Schematic

This is a Simple Train And Slot-Car Controller Circuit Diagram. As shown, a 555 timer (Ul) is configured as an astable multivibrator (oscillator) with a 400:1 duty cycle and a frequency of 40 Hz. When power is applied to the schema, capacitor CI (connected to pin 6 of Ul) is discharged and the output of the 555 (which is used to sink current) is low. Capacitor CI begins to charge via R1 and R2 toward the positive supply rail. When the charge on CI reaches about 66% of + V, the output of Ul at pin 3 goes high. At that point, CI begins to discharge through R2.

Train And Slot-Car Controller Circuit Diagram

When the charge on CI decreases to about 33% of the supply voltage, the output of Ul returns to the low state, and the cycle is repeated until power is removed from the schema. When the output of Ul is low, C3 is discharged into Ul via transistor Q2. When Ul pin 3 goes high, C3 charges through a current source that consists of Dl, D2, R3, R4, and Ql. The charge/discharge cycling of C3 produces a stream of pulses that are fed to the inverting inputs of U2A and U2B (an LM358 dual op amp). Two voltage-divider networks (R7, R8, R9, and RIO, Rll, R12) set the reference voltage that is applied to the noninverting inputs of U1A and U1B at pins 3 and 5. Potentiometers R9 and R12 set the low-level duty cycle (5 to 10%) of U1A and U1B.

They are adjusted so that the train headlights glow, but the motor hums only slightly. Potentiometer R3 adjusts the ramp rate of C3 for 100% duty cycle at the full throttle setting. A double-pole, single-throw switch (SIA and SIB) is used to place R3/C4 and R4/C5 in the schema. The R5/C4 and R6/C5 combinations cause the reference voltages presented to the noninverting inputs to U2A and U2B to change very slowly when the throttle is turned up and down. When the ACL/DCL switch is turned off, the resistance of the throttle-divider networks are much smaller than those of R5 and R6, so the reference voltages on C4/C5 change `instantly` to the new throttle setting.

The output drivers consist of resistors R13 and R15, and transistors Q3 and Q4 for output` `; and resistors R17 to R20, and transistors Q5 and Q6 for output `B.` Components R13/R16/Q3 and R17/R20/Q5 limit the output drive currents of Q4 and Q6 to about 3 A each. Resistors R14/R15 and R18/R19 turn on Q4 and Q5, respectively, before the breaKOhmver voltage is reached to prevent damage to the output drivers and dissipate the energy that is stored in an inductive field (such as in a motor). The power supply delivers 18 V to the track, ltage regulator U3 (a 78L09 9-V, 100-mA voltage regulator) supplies power to the control diagram

Fan Controller Using Just Two Component

Fan Controller Using Just Two Component Circuit diagram. The Maxim MAX 6665 (www.maxim-ic.com) provides a complete temperature-dependent fan controller. It can switch fans operating at voltages of up to 24 V and currents of up to 250 mA. The IC is available from the manufacturer in versions with preset threshold temperatures between +40 °C (MAX6665 ASA40) and +70 °C (MAX6665 ASA 70). The device’s hysteresis can be set by the user via the HYST input, which can be connected to +3.3 V, connected to ground, or left open. The following table shows the hysteresis values available:

HYST = Hysteresis
open = 1 °C
ground = 4 °C
+3.3V = 8 °C

Fan Controller Using Just Two Component Circuit diagram:

Fan Controller Circuit Diagram

The other pins of the SO8 package are the FORCEON input and the status outputs WARN, OT and FANON. The test input FORCEON allows the fan to be run even below the threshold temperature. The open-drain output WARN goes low when the temperature rises more than 15 °C above the threshold temperature, while the open-drain output OT indicates when the temperature is more than 30 °C above the threshold. The push-pull output FANON can be used to indicate to a connected microcontroller that the fan is turned on.

Author: G. Kleine Copyright: Elektor Electronics

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

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