Battery charger with LM317


Posted on Mar 25, 2013

An LM317 voltage regulator is configured as a constant-current source. It is used to supply the 50 mA charging current to S01-S06, an array of AA-cell battery holders. Each of the battery holders is wired in series with an LED and its associated shunt resistor. When the battery holder contains a battery, the LED glows during charging. Each battery holder/LED combination is paralleled by a 5.1-volt Zener diode. If the battery holder is empty, the Zener conducts the current around the holder.


Battery charger with LM317
Click here to download the full size of the above Circuit.

A timing circuit prevents overcharging. When power is applied to the circuit, timing is initiated by IC2, a CD4541 oscillator/programmable timer. The output of IC2 is fed to Ql. When that output is high, the transistor is on, and the charging circuit is completed. When the output is low, the transistor is off, and the path to ground is interrupted.




Leave Comment

characters left:

New Circuits

.

 


Popular Circuits

Feedback oscillator
12V to 9 or 6 v converter
Autonomous Parallel Parking RC Car
High impedance DC Voltmeter by IC CA313048
ac TRIAC dimmer circuit design help (resistive load)
cr vacuum tube detector radio
maximite stepper motor interface
app note high voltage led applications
ph d scientist infrared sensor
Vu meter stereo circuit
Mini Audio Signal Generator
1.5V-powered microphone signal amplifying circuit
Using optocouplers lighting circuit lights a delay



Top