Description: The project features a constant voltage, constant current NiCd charger originally in QST Dec82. The charger is built around 8 discrete transistors with a fine adjustment control of the current and voltage. The output current is 700 mA max. Requires a simple AC wall mount transformer for the power source.

Description: The project replaces the Chapter 27 Figure 68 battery charger that used the UC3900 IC. The UC3900 IC has been replaced with the UC3906 IC. This charger is designed to charge the 12 VDC gel cell type batteries between 1 to 8 AHr. The circuit is designed around the UC3906 charger IC and uses a TIP42 for the pass transistor. This makes a simple charger for those gel-cell batteries.

Description: This circuit is designed to trickle charge small lead acid batteries. The board has positions for three outputs, each output turns on the charge current to each battery individually, and then cycles to the next battery based on a 555 timer. Power is supplied from a wall transformer. The major components required are a 555, 4017, three IRF511, and 7812.

Description: This is a 1.5" square board that uses a 7805 IC. The output is variable and can be adjusted to charge up to 10 cells in series.

Description: This circuit has three level indicators: over range, in range, and under range. Circuit uses LM339 and 2N3904.

Description: This is a simple circuit that will continuously source 13.8 VDC at three amps when the supply battery drops to 9.0 v. Circuit uses LT1070C

Description: There are two versions of the power supply done in the article. The MOSFET IRFP064 is used for the pass device which is more efficient than a bipolar transistor. The regulator is the common 723 with a quad opamp 324 used for over voltage sensing and protection. An SCR is used to clamp the voltage. The 324 also shuts down the 723 in an over voltage condition thus not loading the supply.