Battery charger using LM350


Posted on Feb 5, 2014

Here is a simple circuit using IC LM 350, which can be used for charging 12V lead acid batteries. This circuit is perfect for constant charging  12V lead acid batteries. The circuit is designed as a constant voltage source with a negative temperature coefficient. The transistor Q1 (BD 140) is used as the temperature sensor. The transistor Q2 is


Battery charger using LM350
Click here to download the full size of the above Circuit.

used to prevent the battery from discharging through R1 when the mains power is not available. The circuit is designed based on the voltage regulator IC LM350. The output voltage of the charger can be adjusted between 13-15 V by varying the POT R6. The LM350 will try to keep the voltage drop between its input pin and the output pin at a constant value of 1. 25V. So there will be a constant current flow through the resistor R1. Q1 act here as a temperature sensor with the help of components R6/R3/R4 which more or less control the base current of Q1. As the emitter/base connection of transitorQ1, just like any other semiconductor, contains a temperature coefficient of -2mV/ °C, the output voltage will also show a negative temperature coefficient. That one is only a factor of 4 larger, because of the variation of the emitter/basis of Q1 multiplied by the division factor of P1/R3/R4. This results in approximately -8mV/ °C. The LED will glow whenever the mains power is available.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Perfboard Hackduino Arduino-compatible circuit
    All-analog automatic night light circuit
    Transistor current limit circuit power handling
    AD Design
    lm1881 video sync for tv and lcd monitor separator
    one ic two tones siren with
    Eds Medieval Madness Pinball Machine
    Nixie Clock Version 1
    28 LED Clock Timer
    Circuit of RIIA phono pre-amplifier op-27
    UPC1651 FM wireless microphone circuit



    Top