Voltase hobby: flasher

Showing posts with label flasher. Show all posts

Friday, October 31, 2014

Dual 3v White LED Flasher and Dual 1v5 White LED Flasher

This circuit alternately flashes 2 white LEDs, on a 3v supply and produces a really bright flash. The circuit produces a voltage above 5v if the LED isnt in circuit however the LED limits the voltage to its characteristic
voltage of three.2v to 3.6v. The circuit takes concerning 2mA and is actually a voltage-doubler (voltage incrementer) arrangement.

The 1k charges the 100u and therefore the diode drops zero.6v to prevent the LED from setting out to illuminate on 3v. When a transistor conducts, the collector pulls the 100u down towards the 0v rail and therefore the negative of the electro is actually concerning 2v below the 0v rail. The LED sees 3v + 2v and illuminates terribly brightly when the voltage reaches about 3.4v. All the energy within the electro is pumped into the LED to supply a really bright flash.

DUAL 1v5 WHITE LED FLASHER
This circuit alternately flashes 2 white LEDs, on a 1.5v supply and produces a really bright flash. The circuit
produces a voltage of concerning 25v when the LEDs dont seem to be connected, however the LEDs scale back this as they need a characteristic voltage-drop across them after they are illuminated. dont use a offer voltage above one.5v.

The circuit takes concerning 10mA. The transformer consists of thirty turns of terribly fine wire on a 1.6mm slug 6mm long, however any ferrite bead or slug will be used. the amount of turns isnt crucial. The 1n is very important and using the other worth or connecting it to the positive line can increase the provision current.

Using LEDs apart from white can alter the flash-rate considerably and each LEDs should be identical color.

Monday, September 1, 2014

3v Low Battery Voltage Flasher

Many battery powered devices use two AA alkaline cells. Often you will not know when it is time to replace the batteries until the device powered by them actually stops operating. The hobby schema below can be connected to a 3v battery, to give you some warning when the battery is nearing its end of life.

It will flash a LED when the battery voltage drops to about 2.4 volts. The electronic schema draws only 1ua of current in standby mode and jumps to only 20ua when flashing, so it can safely be included without depleting the battery energy. A voltage detector IC from Panasonic (Microchip also makes similar devices) is used to monitor the battery voltage. The device’s open drain output swings low, when the battery voltage is below 2.4 to 2.5 volts. This action turns on the two transistor oscillator schema, which drives the LED with short current pulses lasting only 2ms.

Source: DiscoverCircuits