universal battery charger schematic


Posted on Feb 5, 2014

The charger can charge a single cell or a number of series-connected cells up to a maximum of 18V. Power transistors Q1 and Q2 are connected as series regulators to control the battery charger`s output voltage and charge-current rate. An LM-317 adjustable voltage regulator supplies the drive signal to the bases of power transistor Q1 and Q2.


universal battery charger schematic
Click here to download the full size of the above Circuit.

Potensiometer R9 sets the output-voltage level. A current sampling resistor, R8 (a 0. 1 ohm/5W unit), is connected between the negative output lead and circuit ground. For each amp of charging current that flows through R8, a 100mV output is developed across it. The voltage developed across R8 is fed to one input of comparator U3. The other input of the comparator is connected to variable resistor R10. As the charging voltage across the battery begins to drop, the current through R8 decrease. Then the voltage feeding pin 5 of U3 decreases, and the comparator output follows, turning Q3 back off, which completes the signal`s circular path to regulate the battery`s charging current.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Audio Mini FM Receiver
    AM Radio built around LM555
    Circuit diagram 500mW FM PLL transmitter 88-108MHz using LMX3206 and PIC16F870
    wireless picaxe based water tank level sensor
    DMX Controlled Theatrical Phone Ringer
    Radio Jammer
    45 Years Anniversary of Walter Bruchs PAL Color Television
    Spitfire/GT6 Relay and Blinker Information
    Color offset printing circuit



    Top