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Topic: High level switching with PNP darlington (Read 12327 times) previous topic - next topic

drjiohnsmith

looks good for an input,

I prefer to see switch on the high side of the opto, not the low side,
     so when switch open, no 12 volts on the board,
         ( you open the switches to work on the arduino and short something it goes bang )

you dont need to join the grounds at the opto,
    the right and left sides are isolated,
        provided the led in the opt lights , the opto works,
       
btw : check that 300 ohm value, the opto is only going to need a few mA, check the data sheet the resistor might be a bit low.



as for outputs, I cant remeber what your using ,sorry

   

jonh

Ok so i have a new circuit to protect the arduino using optocouplers i plan to use 4 x 4 channel devices as above with complete isolation of the arduino electrics with the power board electrics using a shield the circuit diagram for 1 channel is as below :



I've used a zener to regulate the 12v on the new shield to give me 5v so it will match the original input from the arduino output pin through the optocoupler .

Any comments approciated

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