Monthly Archives: July 2010

Blinking LED Emulates Incandescent Bulb

Posted on July 15, 2010 by Rend
FADING LED

This is flashing LED circuit emulate the turning of incandescent lamp.  The characteristic of incandescent lamp is that they can’t abruptly change the luminosity. This circuit is used to fade in and fade out the on and off state change.   … Continue reading →

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Wireless Telephone Line Spy

Posted on July 12, 2010 by Rend
PHONE BUG

This is a phone bug circuit. This wireless telephone line spy circuit can be used to transmit the phone conversation to a nearby FM radio. This circuit must connected to a normal phone line.  Here is the schematic diagram of … Continue reading →

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Eco-Friendly Power-On Indication

Posted on July 8, 2010 by Rend
POWER ON

This is a power on circuit that works temporarily only when the power is turned on, this  LED illuminates for a few seconds, then turns off again.   This design is eco-friendly since it consumes only a little power at the … Continue reading →

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