How to prevent back feeding a parallel AC circuit

Thread Starter

Macdenewf

Joined Nov 27, 2023
2
Beginner question. Looking to make sure I don’t fry something. Setup. 12v AC feeding a gate keypad. When the code is entered 12v AC is fed to an electronic latch. NC latch so only remains open for as long as there is power. To make it smart I planned on paralleling 12v AC to the latch from a smart dry contact. Fearful that the 12v applied at the latch will cause damage to the keypad.
I know you use a diode on a dc circuit to prevent back feeding voltage from the latch to the keypad. Can’t recall if you can use a diode on both wires of AC to accomplish the same.
thanks in advance.
 

Dodgydave

Joined Jun 22, 2012
11,303
No you can't use a diode on AC, but the keypad might have a relay output on it to drive the latch, so it won't hurt it, can you take pictures of the keypad?
 

Thread Starter

Macdenewf

Joined Nov 27, 2023
2
I think I answered my own question once I re looked at the diagram. I was thinking I needed to route power to the latch. Turns out it has an option for a button. I can use relay to close the circuit.
Thanks
Mac
 

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