Posts Tagged ‘7815’



12V input, 12V battery charger by 555,7815

Wednesday, January 30th, 2008

The charger consists of two stages: The first is a capacitive voltage doubler, which uses a 555 timer IC driving a pair of transistors connected as emitter followers, which in turn drive the voltage doubler proper. The doubler has power resistors built in, which limit the charging current. BUY Lead Acid Battery Charger Electronic Module [...]

Check the milli-Ampere-hour capacitance of your rechargeable NiCad batteries

Wednesday, August 29th, 2007

Introduction With this mAh meter you can check the mAh capacitance of your NiCad or NiMH rechargeable batteries Normally the cheaper NiCad AA-type cells have a capacitance of 500-750mAh (NiCAD) the more expensive NiMH AA-cells types are up to 1800mAh. I built this circuit because the capacitance of some of my older NiCad batteries seemed [...]

Dual Regulated Power Supply +/- 15V 7815,7915

Wednesday, July 25th, 2007

In this circuit, the 7815 regulatates the positive supply, and the 7915 regulates the negative supply. The transformer should have a primary rating of 240/220 volts for europe, or 120 volts for North America. The centre tapped secondary coil should be rated about 18 volts at 1 amp or higher, allowing for losses in the [...]