a/v switch

Printed From: the12volt.com
Forum Name: Relays
Forum Discription: Relay Diagrams, SPDT Relays, SPST Relays, DPDT Relays, Latching Relays, etc.
URL: https://www.the12volt.com/installbay/forum_posts.asp?tid=73293
Printed Date: June 30, 2025 at 5:59 PM

Topic: a/v switch

Posted By: congoman
Subject: a/v switch
Date Posted: February 22, 2006 at 2:52 AM

does anyone know how to make an audio/video switcher using a spdt relay(s)?

I've seen it done before but don't remember the wiring configuration. Just in case one of these days when we're in a jam and we desperately need a a/v switch.

Replies:

Posted By: mustangfoo
Date Posted: February 22, 2006 at 9:39 PM

a lil more info would help, what do u want to happen, for example (you want a neon light to turn on when your amp comes on)

Posted By: the12volt
Date Posted: February 22, 2006 at 9:59 PM

congoman, if you're looking to switch two sources to one input with relays, you will need three SPDT relays and three 1 amp diodes if both sources will share respective audio and video signal grounds. Keep in mind this could be a noisy circuit

Relay 1
85 to ground
86 to switched 12V+
87a to source A left audio + output
87 to Source B left audio + output
30 to left audio + input

Relay 2
85 to ground
86 to switched 12V+
87a to source A right audio + output
87 to source B right audio + output
30 to right audio + input

Relay 3
85 to ground
86 to switched 12V+
87a to source A video + output
87 to source B video + output
30 to video + input

Place a diode across the coil on each relay with the cathode side toward 86 and the anode side toward 85. Terminal 86 on all three realys should be connected to the same switched source.

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Posted By: congoman
Date Posted: February 28, 2006 at 12:27 AM

I'm a little stupid but, what do I do with the negative leads of the rcas?

Posted By: the12volt
Date Posted: February 28, 2006 at 9:43 AM

There is no need to switch the negative leads of the RCA's. Both sources can share respective audio and video signal grounds as I stated above.

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