Can i use this configuration to drive 12 VDC SSR Relay or 12 VDC Coil Relay ? Please suggest do i need to keep 220R Resistor in between 2 Transistor ? If i use as darlington pair directly will it damage PC817 ?
That will drive the relays but you need a diode across terminals 1 and 2 (anode to 1) to suppress the inductive spike of a mechanical relay coil.
The value of R20 is too low, as the opto coupler cannot provide that much current (worst-case, the output current is 50% of the input current).
Thus R20 needs to be at least 1.3kΩ
A Darlington pair will work fine to output more current as long as it's connected the same as you show Q5.
That will drive the relays but you need a diode across terminals 1 and 2 (anode to 1) to suppress the inductive spike of a mechanical relay coil.
The value of R20 is too low, as the opto coupler cannot provide that much current (worst-case, the output current is 50% of the input current).
Thus R20 needs to be at least 1.3kΩ
A Darlington pair will work fine to output more current as long as it's connected the same as you show Q5.
hi , opto coupler cant drive highcurrent , so 220R resistance is very low , check the datasheet for max current can be driven , and use golden V=IR rule to calculate Resistance