13.8V 20A Transformerless Power Supply Circuit
This PSU has been abnormally advised for current-hungry ham radio transceivers. It delivers cautiously about 20Amps at 13.8V. For lower currents, a abstracted accepted attached output, able of 15ma up to a absolute of 20A has been added. Let us see what we accept got here. The ability agent should [...]

18w Audio Amplifier with Power Supply
Amplifier parts:
P1_____________22K Log. Potentiometer (Dual-gang for stereo)
R1______________1K 1/4W Resistor
R2______________4K7 1/4W Resistor
R3____________100R 1/4W Resistor
R4______________4K7 1/4W Resistor
R5_____________82K 1/4W Resistor
R6_____________10R 1/2W Resistor
R7_______________R22 4W Resistor (wirewound)
R8______________1K 1/2W Trimmer Cermet (optional)
C1____________470nF 63V Polyester Capacitor
C2,C5_________100µF 3V Tantalum bead Capacitors
C3,C4_________470µF 25V Electrolytic Capacitors
C6____________100nF 63V Polyester [...]

This battery charger is for 12V Seales Lead Acid (SLA) battery. It is actually a half-wave rectifier. It only charges the battery on every half cycle. The plug pack doesn’t like this as it leaves residual flux in the core of the transformer and causes it to overheat.

There are a number of points we need [...]