35W Power Audio Amplifier based LM391

Here the 35W power audio amplifier circuit based on LM391. Inductor L1 is constituted by 20 coils of wire, with thickness 0.9mm, round resistor R16. The transistors Q3-4 are the final amplification section, it should be placed on heatsink. If are used the Q3-4 in packing TIPxxxx they can be placed straight above in PCB.… Read More »

6V / 9V / 12V Battery Charger with Constant-Current Charging

This is the circuit diagram of battery charger which has many important features such as current-constant charging, overcharge protection, short-circuit protection, deep discharge protection and more. The constant-current charging is a popular method for lead-acid and Ni-Cd batteries. In this circuit, the battery is charged with a constant current that is generally one-tenth (1/10) of… Read More »

Variable / Adjustable DC Power Supply 1.2V – 25V using LM338K

This is variable DC power supply circuit, or we can call it adjustable DC power supply which give us a 1.2V-25V output voltage. The power supply schematic above is taken from the datasheet of regulator LM338K manufactured National Semiconductor. The circuit uses IC LM338K as the voltage regulator, so we will get the stable and… Read More »

DC to DC Converter +5V to +12V

This is the fixed 5V to 12V DC to DC converter. The circuit application converts input voltage of 5V (range 4.5V-5.5v) to 12V fixed regulated DC output. The circuit built based National regulator monolithic IC LM2586 which is specifically designed for flyback, step-up (boost), and forward converter circuit applications. The LM2586 will require a heat… Read More »