Automatic Emergency Light Project. When mains is absent, relay RL2 is in deenergised state, feeding battery supply to inverter section via its N/C contacts and switch S1. The inverter section comprises IC2 (NE555) which is used in stable mode to produce sharp pulses at the rate of 50 Hz for driving the MOSFETs. The output… Read More »
This is the circuit diagram of digital clock based on IC MM5314N. The clock display uses 6 pieces of 7 Segment LED with format HH:MM:SS. The power supply for this circuit already included, so you can connect this circuit directly to the mains. The DC supply is about 5-12V.
This is indicator circuit to indicate that there is blown fuse, it will show the condition of fuse through LEDs. This circuit works for fuse 220V mains. This compact circuit is very useful and reliable. It is a low cost circuit which use very few components. Generally, when an electronic device indicates no power, the… Read More »
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 1.5W audio amplifier circuit design based on wide bandwidth, low distortion power IC SSM2211 from Analog Devices. This circuit is simple, inexpensive and easy to built with only contains few components. The SSM22111 is a high performance audio amplifier that delivers 1 W RMS of low distortion audio power into a bridge-connected 8… 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 simple and low cost 3 channels mini audio mixer circuit diagram. This circuit supplied using 9V power supply. There are high/low-sensitivity switchable inputs for each input channel and each channel used low noise and high gain transistor of BC550C.
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 a simple low cost circuit of an active FM booster that can be used to amplify the FM band signal, so you can listen the FM channels/programs from distant FM stations clearly. The circuit make use of a common-emitter tuned RF preamplifier wired around VHF/UHF transistor 2SC2570. (Only C2570 is annotated on the… Read More »