Relay help

Question

Hello,

I am trying to find a way to turn off a circuit with a red light, when another circuit with a green light is closed. When the green light circuit becomes open, the red light should turn back on.

Any help with this problem would be greatly appreciated.

-Thanks

jw0752 · Accepted Answer

Hi Mark, There are many permutations of what you are describing so it is unlikely that I have drawn the correct schematic but here is a place to start anyway. John

jw0752 · Answer

Hi Mark, I drew this schematic very quickly and the RL is just a left over. If there were more than one relay they would be numbered RL1, RL2, etc. The SW2 switch can be replaced with a wire and SW1 can be just a washer touching two separated contacts. Have Fun! John

COMPACT · Answer

Modded for a single power source

COMPACT · Answer

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Here it is in reality. I used LEDs with current limiting resistors as the coloured lights.

COMPACT · Answer

Is this what you are trying to accomplish? When the Green circuit is OFF by the switch - the Red Circuit is ON by the relay. When the Green circuit is ON by the switch - the Red Circuit is OFF by the relay. The NO contact on the Relay stands for Normally Open The NC contact on the Relay stands for Normally Closed (With Normally meaning the state when there is not power to the relay coil.)

COMPACT · Answer

That's a diode. Some relays have them built in whilst others need to have them added. When a relay coil is de-energised the collapsing magnetic field creates feeds power back into your circuit in the wrong direction and potentially with a very high voltage. The diode dissipates this unwanted power in a controlled manner.

COMPACT · Answer

If you want a changeover switch just use a SPDT (Single Pole Double Throw) switch.

Relay help

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