Simple regulated power supply with overcurrent trip


Posted on Dec 20, 2012

The 15v zener is fed via the 4K7 resistor from the input. With 0.6v across the base - emitter of the PNP transistor, this establishes a voltage of 14.4 across the 3K3, so there must be a current of nearly 4.4mA through the 3K3. This current is available to feed the emitter of the transistor - provided that the diode D1 doesn`t pinch any of it. However with no load on the output, some of this current flows through the PNP to turn on the BFR39 and the 2N6254 which will conduct.


Simple regulated power supply with overcurrent trip
Click here to download the full size of the above Circuit.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    Soil-moisture-meter
    Tube Mic Pre-Amp
    level shifting Increasing Voltage
    555 Capacitor Tolerance Adjustment circuit
    PCI-Bus with 3.3V Auxiliary Hot Swap Controller
    Interfacing to LVDS with the NI 655X Digital Waveform Generator/Analyzer
    Cyclotron II
    USB-Atmel External 3.3V Level Converter
    The LM3886 BTL amplifier



    Top