Need a relay controller

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rtm038

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Hello all,
I need to find a simple relay controller to complete my project. I'm using a 12+VDC, 30-amp SPDT Bosch-type relay and want to control it via a single, normally-open momentary switch. Basically I'm looking for the controller to control the relay like so:

1. Press & release the normally-open momentary switch once and the relay coil energizes and remains energized after the switch is released.

2. When the relay coil is energized, pressing & releasing the normally-open momentary switch will cut power to the relay coil.

3. When the relay coil is energized, taking power away from the relay controller will cut power to the relay coil.

Does anyone know where I can get a controller that will permit all of these functions?

Thanks
Ryan
 
Thanks for the reply. Well, I've been searching Google for different circuits and have tried out a few, but they never seem to work. I'm convinced that making something electronic might be beyond my abilities....
 
You might want a regulator. On the flip flop, the button will toggle a pin, that will cause the Q pin to high and low. You will need a transistor to drive the relay, and a couple resistors. A diode on relay coil.

Here is another link **broken link removed**

You can make a bi-stable flip flop from transistors and just use half the circuit.

**broken link removed**
 
O.K. Maybe I'll try that bi-stable circuit and see what happens. Now the other thing I'm having trouble with, which could be the cause of my previous failures, is determining which side of the capacitor is the + and which is the -. Since most of the capacitors I've been using aren't marked, how can I identify each side? Plus, when I go to Radio Shack to buy my parts, how do I know type of capacitor (ceramic, metal, etc.) and transistors (power, switching, etc.) to buy, since the schematics don't usually specify?

Thanks
Ryan
 
If you are still looking, try this site:

**broken link removed**

Use the circuit labelled "Single Transistor Relay Toggle Circuit"
 
You will need some support electronics to operate like you want with only one momentary switch.

However if you use a relay with DPDT contacts and use instead a 3 position spring loaded rotary switch, (left to stop, right to start, center return) you could use a standard motor control wiring scheme. The normally open start contacts would pull in the relay, one normally relay contact would 'seal' (latch) the relay coil power. Then normally closed contacts would open the relay coil when turned to the off position, dropping out the relay coil power.

It's one of several common industrial motor control circuits. The same scheme will work with two momentary switches, one with NO (start switch) contacts the other with NC (stop switch) contacts. The trick is in using an extra set of relay contacts to perform the 'latching' function.

Lefty
 
Last edited:
Leftyretro said:
You will need some support electronics to operate like you want with only one momentary switch.

Lefty
Click to expand...
You could use a transistor to provide the "normally Closed" function in conjunction with a SPST momentary switch.
 
I always thought this was a pretty slick, minimum electronics push-on/push-off relay circuit:

**broken link removed**

If I remember right, the relay has a 12v coil, and the resistors are selected to match the coil's DC resistance.

Ken
 
Adding A Smalldpdt Relay And A Dpdtmomentary Contact Switch Should Enable You To Drive Your Presant Contactor And Satisfy Your Logic Requirements Without Geting Overly Involved With Caps An Transistors Etc.
Edge
 
Perhaps you might try not putting capital letters on every word?, this isn't correct practice, and it makes your posts difficult to read.
 
Not the whole story .......


Ryan, you are probably not telling us the whole story, because a normal person would just go and out and buy a push ON, push OFF switch!
 
You could use the "el-cheapo" method of using a latching-relay, to apply the 12VDC to your 'Heavy Duty' relay? Eg. use a relay to control the relay, I realise it's a bit of overkill but it's an easy way out.

See **broken link removed** for the type of relay I am talking about.
 
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