relay Do I need a protection diode here

Posted on Feb 5, 2014

I have an automotive relay (from a scan of a workshop manual I`m afraid) which is rather more complexly wired up than the relays I`m familiar with. In this diagram: B/G - holds high if another condition is met (engine temp too high), to prevent the relay energising. (As far as I can tell. this is the correct logic for sure, not sure if it tech

relay Do I need a protection diode here
Click here to download the full size of the above Circuit.

nically works that way!) I understand how the relay works at the moment. However, what I plan is to cut (L) and insert a device which will prevent the relay energising unless some further conditions are met. This is achieved with some logic gates and an output transistor, which will `join` L when my device allows it. What I can`t tell is if I need a protection diode across the relay to protect my transistor And if I do, would this interfere with the logic provided by the combination of L, L/B and B/G

Leave Comment

characters left:

Related Circuits

  • New Circuits



    Popular Circuits

    Turn an old PC into a multi-channel pulse generator, for PWM/servo/stepper
    Sensitive Low-Current-Drain Motion Detector
    Tron Disc with .NET Microframework
    Electronic jam circuit diagram
    How to connect a crystal oscillator to generate Square wave
    Automatic coming/leaving home light
    SPI-Flash Programmer 3.7
    W7800 by the application circuit composed of power supply tracking
    Having a cold junction compensation Remote Isolated Thermocouple transmitter circuit diagram ISO102 XTR101
    The timing of the flip-flop circuit composed of a photodiode etc.