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 »
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 the circuit diagram of car audio system anti theft security which can be effectively used to protect and secure your expensive car audio system from stealing. This simple circuit designed based on popular CMOS NAND chip CD4093,. When the circuit is switched on via switch S1, the indicator LED1 will glow and the… 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 circuit diagram of Digital Tachometer / Digital RPM Meter which can be used for cars or motorcycles with 2 and 4 stroke petrol engines with any number of cylinders and contact breaker or electronic ignition systems. May be used as a general purpose revolution counter. Digital Tachometer Mainboard Scheme: