This is a simple
circuit to charge a 7.2V NiCad battery in around 5 hours at 1/4 the
cell capacity rate.
The charging current on my prototype was around 300mA.
The LED in
the circuit comes on when a battery ic connected to indicate that
charging is in progress.
In the schematics I have shown Wago screw clamps for all power connections, you can use normal PCB holes.
Warning
This circuit has a 230V AC mains transformer. Only build this circuit if you are competent with AC mains powered equipment and the dangers involved.
|
Part |
Value |
Device |
Package |
Description |
|
C1 |
1000uF |
CPOL-EUE5-13 |
E5-13 |
Electrolytic capacitor |
|
C2 |
100nF |
C-EU050-030X075 |
C050-030X075 |
Ceramic disc capacitor |
|
CN1 |
BATT |
W237-02P |
W237-132 |
WAGO SREW CLAMP |
|
D1 |
1N4004 |
1N4004 |
DO41-10 |
DIODE |
|
D2 |
1N4004 |
1N4004 |
DO41-10 |
DIODE |
|
F1 |
200mA |
SH22,5A |
SH22,5A |
20 mm fuse holder, PCB mount |
|
MAINS |
W237-02P |
W237-132 |
WAGO SREW CLAMP |
|
|
R1 |
120 |
R-EU_0309/12 |
0309/12 |
1/2 W resistor |
|
R2 |
15R |
RKH206-8 |
KH206-8 |
5W power resistor |
|
TR1 |
EI30-2 |
EI30-2 |
25VA 12Vx2 TRANSFORMER |
|
|
U1 |
LED5MM |
LED5MM |
A 5 mm LED |
Click the above image for a full schematic.
By Ian Stedman, 27th August 2003
Updated 23 February 2010