Schematics > Power > NiCd - NiMH Charger
NiCd - NiMH ChargerThe charger is build around a
LM317 (click to download
datasheet) adjustable regulator.
The charge starts when a battery is connected between pins JP1-JP4 or JP2-JP4 or
JP3-JP4.
For example, if a battery is connected to JP1-JP4 pins then the current that
flows cause a voltage drop to R1, then D1 causes a voltage drop of 0,7 volts and
Τ1 conducts. Then through transistor's emitter flows a current that comes from
Adjustment pin of LM317.
Diode D4 prevents current to flow from battery back to the charging circuit.
Resistors R1,R2 and R3 adjusts the charging current and it's value is given from
: Rx=(1,25 + 0,1) / I , where x = 1,2,3.
I is 1/10 of the battery's charging capacity. For example if battery has a
rated capacity of 1700mA then Ι=170.
The input voltage must be at least 3 times the battery's voltage. For example
an input voltage of 25V can charge a 8,4V (9V) battery.
R3 is 1/2 Watt and R1 and R2 it's 1/4 Watt.
Download PCB in PDF format
| Pins |
Battery type |
| JP1 - JP4 |
AAA |
| JP2 - JP4 |
AA |
| JP3 - JP4 |
PP3 & 6F22 |
Title: NiCd - NiMH Charger
Source: www.electronics-lab.com
Published on: 2005-02-03
Reads: 699
Print version:  Other schematics from Power
Variable Voltage and Current Power Supply Simple Car Battery Charger Ultra low drop linear voltage regulator Dual Polarity Power Supply Ni -Cd Batteries Charger 0-30 vdc stabilized power supply with current control 0.002-3 a Voltage Inverter II High and Low Voltage Cutout with delay and Music 500W low cost 12V to 220V inverter 12V Inverter
Schematics > Power > NiCd - NiMH Charger | 
Home
