This is the circuit diagram of electronic quiz button table. This circuit is simple, easy to built and of course it is not expensive. This quiz circuit used for four game participants. It determines the contestant who first presses the switch (S1 through S4) to answer a question and locks out the remaining three entries… Read More »
This is the circuit diagram of 24 Watt class A linear audio amplifier, built and tested by Marc Klynhans from South Africa. The supply voltage can be between 34V and 46V and the quiescent current should be set to 1.7A measured through R25 (a voltage of 0.75V must be measured over R25 for a quiescent… Read More »
This is the circuit diagram of 18W audio amplifier. The circuit is quite simple and inexpensive to built. It uses a pair of power transistor TIP41A and TIP42A for single channel operation. The power supply used for this circuit is dual polarity (splitted) power supply, use center tap transformer to build this kind of power… Read More »
This is 220V 800W lamp flasher circuit directly connected to 220V mains. One or more lamp which has high consumption / power can be used. It is ideal for signage warning or danger, this circuit flickers the lamps. The work of this circuit is simple. The 400V capacitor, the bridge rectifier, the zener diode and… Read More »
This is LED emergency light that will turned on automatically when mains supply fails, and turned off when mains power resumes. This circuit produces highly bright because the use of ultra bright white LEDs. This circuit also has its own battery charger. When the battery is fully charged, the charging process will stop automatically.
This is laptop / notebook protector circuit to protect your laptop or notebook or netbook from being stolen. Fixed in-side the laptop case, it will sound a loud alarm when someone tries to take the laptop. This highly sensitive circuit uses a homemade tilt switch to activate the alarm through tilting of the laptop case.… Read More »
This is the speaker protection circuit, provides stereo speaker protection and prevents switch-on clicks and DC components on the output of the amplifier connected.
This is a simple and easy built electronic candle circuit which build using TTL (transistor-transistor logic) that are 74LS164, 74LS86 and 74LS00. This circuit will give the effect of candle light in a normal 220V electric bulb lamp. A candle light, as we all know, resembles a randomly glimmering light. So, the objective of this project… Read More »
This is the schematic diagram of Infrared (IR) cordless headphone. Maybe it also can be called “wireless headphone”, but it use infrared as sound signal carrier. It use a pair of circuit diagrams that are IR transmitter and IR reveiver. Using this low-cost project one can reproduce audio from TV or other electronic devices without… Read More »