microcontroller driving relay


Posted on Feb 6, 2014

I usually use an NPN Bipolar transistor to do the relay switching, mainly because my relays are 12v coil rated, but it also keeps everything nice and seperated. and yes i add a diode. with no problem. ( do I or did I need to drive it with a transistor ) but it seam like radio shack is getting out of the parts business. I`ve got to place a order wit


microcontroller driving relay
Click here to download the full size of the above Circuit.

h digikey and though I mite find something better and cheaper. If you know the coil resistance it`s easy to calculate if you need a transistor. If it`s too low (say 125 ©) then you can use two pins to provide 40mA. Make sure you connect between the pins and 5V as the pins can sink more than source. The 100R series resistor is only required if the supply voltage is too high for the coil. The schematic also lacks the all-important back EMF protection diode.




Leave Comment

characters left:

Related Circuits

  • New Circuits

    .

     


    Popular Circuits

    How to connect LED's directly to MAINS
    Photomultiplier output-gating circuit
    Programmable Identifier
    Ambulance sirens circuit
    testing troubleshooting inverter
    electrometer schematics
    gic
    Sound card microphone
    555 tone generator circuit
    HIGH VOLTAGE PULSE SUPPLY
    DK-5A, DK-5AD AC power control circuit



    Top