120W Power Amplifier + Power Supply

This is 120W power amplifier schematic using TO-3 package complementary transistors, NPN and PNP polarity. The well-known power transistor pair of 2N3055 and MJ2955 used in this circuit.  +/- 50V symmetrical (split/dual polarity) power supply with minimum 3A electric current should be used for maximum performance.

0-24VDC Digital PIC Power Supply

This is 0-24VDC digital PIC power supply circuit. This variable power supply controlled with PIC microcontroller. There is LCD display in this circuit which will show the actual value of power supply output. This power supply use push on switch to adjust the output voltage and current value. Schematic Diagram: Component List: C1 = 2000uF… Read More »

Bench Power Supply I

This is bench power supply circuit for multi purpose usage… This bench power supply features three solid-state DC power supplies. The first supply gives a +1.5 to +15 volts at 1 ampere. The second supply gives a -1.5 to -15 volts at 1 ampere. The third has a fixed 5V at 3 amperes. All  DC… Read More »

15W FM Transmitter using BLY88C

This is long range FM transmitter with transmision power output is up to 15W. This 15W FM transmitter use power transistor BLY88C as the main transmitter amplifier. Building a good FM transmitter(88-110Mhz) begins with getting a good schematic. You don’t have to understand the precise working of the transmitter to build it. But some basic… Read More »

Automatic Switching-on Emergency Light

Automatic Switching-on Emergency Light The schematic diagram shown right here is the automatic switching-on emergency light circuit which is controlled using IC. The most important capabilities of this circuit are: automatic switching-on of the light on main power failure and battery charger with overcharge protection. When mains electrical power is absent, relay RL2 is in… Read More »

4W Audio Amplifier using Transistor TIP41

This 4W Audio Amplifier circuit is powered by 2 pieces of transistor TIP41. The circuit is very simple and incorporates darlington output transistors that will provide more than enough output current than is needed to drive a 3-ohm speaker. The 4W audio amplifier circuit is very simple and incorporates darlington output transistors that will provide… Read More »

Basic UPS Circuit 5V and 12V DC

The above diagram is a basic Uninterupted Power Supply (UPS) circuit. This basic UPS circuit is a very simple and inexpensive. This circuit can be adapted/modified for other regulated and unregulated voltages by using different regulators and batteries. For a 15 Volt regulated supply, you may apply two 12V batteries connected in series (it will… Read More »