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Back in Black
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Discussion Starter #1
I have searched but no luck. I am doing a special project in which I need a relay. I have a negative output device that needs to trigger a relay then the relay send a negative signal to something. I seen several reverse polarity relay diagrams and other stuff but not this. Any ideas or help? I already have the negative output device I hope I do not need a positve output device then convert to negative.
 

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# 12/50 Ignite LE
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Assuming for a -12v dc system, any 12v dc relay will work. One side of the coil to chassis ground and the other side of the coil to -12v dc to energize the coil and move the contacts. Contact voltage and current does not matter as long as the voltage and current fall within the rated limits of the contacts. Hope this helps.
 

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Discussion Starter #3
Ok understand the 12 v and ground on coil. You said 12v to energize thats my problem my energizing source is a negative output. Then i need a negative output from relay. Can I use a negative to energize relay and send negative out. Does that make since?
Thanks
 

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Ok understand the 12 v and ground on coil. You said 12v to energize thats my problem my energizing source is a negative output. Then i need a negative output from relay. Can I use a negative to energize relay and send negative out. Does that make since?
Thanks
I doubt you have a negative output device. It's more likely what's called a circuit "sink" style digital output.

Most computer controlled digital outputs are power "sinks". It's a lot easier for a transistor switch to provide a ground (or sink) than to provide a voltage (or source). All the outputs on the VRSC ECM work the same way. The START, FAN, and SYSTEM relays, as well as the ignition coils and fuel injectors are all turned on by the computer supplying a ground or power sink for the device. The relay coils, ignition, and fuel injectors all have a constant 12V supply connected and the ECM turns them on by supplying the ground path. I would bet that your device does the same.

Post some instructions (preferably with circuit diagrams) and someone should be able to figure it out.
 

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Not from 'round here
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I have searched but no luck. I am doing a special project in which I need a relay. I have a negative output device that needs to trigger a relay then the relay send a negative signal to something. I seen several reverse polarity relay diagrams and other stuff but not this. Any ideas or help? I already have the negative output device I hope I do not need a positve output device then convert to negative.
If your negative output device will send a negative signal to the "something", why use a relay? Just output the negative directly to the "something"
 

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Back in Black
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Discussion Starter #6
amp difference electro
ok here's more info
rated for 2 amps. Use them to turn on or turn off a device. It can trigger solenoids, our warning light, an LED/resistor assembly, etc. by providing a ground signal. Is this what you are talking about Steve?
I am trying to get it to operate my electric shifter which is a lot higher than 2 amps.
Any ideas?
 

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In this diagram when the -12VDC control power is activated, the contacts will change fro N/C (normally closed) to N/O (normally open).
This will cause the shifter to operate.
I will leave it up to you to decide where the fuse should go. I'll be around today if you're gonna work on it.

Carl
 

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Premium Member
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amp difference electro
ok here's more info
rated for 2 amps. Use them to turn on or turn off a device. It can trigger solenoids, our warning light, an LED/resistor assembly, etc. by providing a ground signal. Is this what you are talking about Steve?
I am trying to get it to operate my electric shifter which is a lot higher than 2 amps.
Any ideas?
Yes that’s what I was talking about. Most semiconductor controlled "outputs" work this way.

Another thing to keep in mind is that the output circuit will need to be protected by using a relay with a diode wired internally across the coil to protect against "EM" (electromagnetic) pulse produced voltage spikes that occur when the coil is de-energized. Here's an example of one with the typical SPDT (single pole dual throw) terminals.

I attached a picture showing a circuit suggestion (fuse can be changed to handle more current up to the relay limit). The green wire will connect to your control channel. The relay will be activated when the green wire is connected to ground (by your device) and the red arrow, connected to the 87 terminal, will be hot when the relay is active.
 

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dont wnat to hi jack post but i have a question

I have change my rear turn signals to dual fil (1157) low watt for driving and high watt for turn and brake. Didn't think about the brake over riding the turn signal, Any suggestions on how to wire one or two relays to make this work?
 

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I have change my rear turn signals to dual fil (1157) low watt for driving and high watt for turn and brake. Didn't think about the brake over riding the turn signal, Any suggestions on how to wire one or two relays to make this work?
If I understand your problem correctly, I can't think of a way to isolate the brake light from the turn signals with a simple relay (or two). You could do this by using two "time-delay" relays (SPDT with instant on and 2 to 3 s off delay). I attached an example circuit (01-MAR-2011: two diodes added to block brake light signal from triggering time delay relay).
 

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