Help with Latching push switch

Thread Starter

hamopp

Joined May 13, 2009
68
Hi
Not sure how to do this yet :confused:
I need to switch a relay on\off, but using a momentary push switch.
1st push = on and 2nd push = off, and need to be latched.

Can a ic be used for this ?

Could do with a diagram to show me the way

Thanks
hamopp
 

Thread Starter

hamopp

Joined May 13, 2009
68
Hi
Thanks for that, can this device be used for 2 switch's by using c2 as the other input ?
so that 2 separate momentary push switch's can switch 2 separate relays (i need to be able to switch about 6 or 8 items), and this would keep the parts to a minimum.
is there a CMOS ver of this device ?

Thanks again for your help
hamopp
 

KMoffett

Joined Dec 19, 2007
2,918
This is a cute circuit to get a push on/push off relay function. The relay coil voltage should be half that of the supply (5-6V for a 12v supply), and the resistors should be equal to the relay's coil resistance.

ken
 

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Mojo2005

Joined Jul 18, 2009
3
I dont have an idea on how to assign values for this very simple circuit (pushon-pushoff). Anybody can do will be much appreciated. I will apply it to my motorcycle to cut the ignition coil (12V) while on parking.
 

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KMoffett

Joined Dec 19, 2007
2,918
I dont have an idea on how to assign values for this very simple circuit (pushon-pushoff). Anybody can do will be much appreciated. I will apply it to my motorcycle to cut the ignition coil (12V) while on parking.
Mojo,

If you look back to my previous post (#6) you will have values that might work. It's the same circuit only redrawn and with the extra set of SPDT contacts added to make it usable. The relay you use depends on the amount current it's contacts can handle, and that depends on the amount of current your ignition circuit draws. Do you know what that is?

Ken
 

KMoffett

Joined Dec 19, 2007
2,918
Mike,

Interesting chip. Ya learn something every day! :)

I went back and re-read the original request.

The simplest solution to hamopp's original problem would be a mechanical push-on/push-off switch controlling the relay (if that's even needed).

For mojo2005, my little circuit would not work as it is always drawing current...on or off. As would your circuit. And he would have to add, minimally, a regulator and two capacitors to get 5V , a relay, and a drive transistor and base resistor. The simplest there is again a mechanical push-on/push-off switch controlling the relay...I think ;)

Ken
 
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Mojo2005

Joined Jul 18, 2009
3
Mojo,

If you look back to my previous post (#6) you will have values that might work. It's the same circuit only redrawn and with the extra set of SPDT contacts added to make it usable. The relay you use depends on the amount current it's contacts can handle, and that depends on the amount of current your ignition circuit draws. Do you know what that is?

Ken
My friend told me its not the ignition line to be cut, its the CDI line. If that so, I need an ordinary 12 volts relay and I will try to use those values.

Thanks Ken
 

KMoffett

Joined Dec 19, 2007
2,918
My friend told me its not the ignition line to be cut, its the CDI line. If that so, I need an ordinary 12 volts relay and I will try to use those values.

Thanks Ken
A 12V relay in that circuit will not work a 12v battery supply. The concept is that the relay coil voltage is 1/2 the supply voltage. An explanation: http://www.oldradio.com/current/pushon-pushoff.htm
You would need a 5V or 6V coil relay.

Ken
 

someonesdad

Joined Jul 7, 2009
1,583
This is a cute circuit to get a push on/push off relay function. The relay coil voltage should be half that of the supply (5-6V for a 12v supply), and the resistors should be equal to the relay's coil resistance.

ken
Ken: thanks for showing that -- I hadn't seen it before and it's just, well, clever. It only consumes 0.3 W when it's on -- not for battery use, but OK for a line-powered device.

I also liked seeing the latching IC.
 
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