today I tell you about new battery charger.It is very important your phone,modems,etc....I explain it step by step.Keep in mind.Do you ready??
Ni-Cd Ni-MH Adjustable Constant Current Battery Charger Circuit
This is a Adjustable Constant Current Ni-MH
or Ni-Cd battery charger circuit. It can be used to get a constant
current power supply. Here is the schematic diagram of the circuit:
| PARTS LIST | |
| R1 | 100Ω |
| VR1 | 500Ω Preset |
| C1 | 0.1µF |
| C2 | 0.01µF |
| D1 | 1N4001 |
| Q1 | BC140 |
| IC1 | LM317 |
This circuit can be adjusted to any value
from a few milliamp to about 500mA. The max current is 500mA because
it is the limit of the BC140 transistor in the current-limiting part
of the circuit.
The input voltage has to be 5.25v above
the required output voltage, because of 1.25v across the
current-limiting section and Approximately 4v is dropped across the
regulator. The LM317 3-terminal regulator will need to be heatsinked.
the LM series of regulator is suitable for
this circuit because they have a voltage differential of 1.25v
between “adj” and “out” terminals.
For example, to charge 4 Ni-Cad cells, just
connect them to the output and adjust the 500Ω preset until the
required charge-current is obtained. The charger will charge 4 Ni-Cad
cells at the same current. But, don’t forget to turn off the charger
before the cells are fully charged or the battery will be over-charged.
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