circuit design help: momentary switch activates/cancels electronic switch

Here is the application:

I have a momentary switch. When I press it, I want to switch something
on (light bulb) and have it stay on even though momentary switch was
released. maybe 500 mA draw.

When I press it again, it turns the light bulb off. How do I do this?
This is in a 12VDC circuit.

Thanks!

Do you particularly want to use that switch or would you be prepared to swap
it for a push-on/push-off momentary action one?

Ken

"matthewuw" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> Here is the application:
>
> I have a momentary switch. When I press it, I want to switch something
> on (light bulb) and have it stay on even though momentary switch was
> released. maybe 500 mA draw.
>
> When I press it again, it turns the light bulb off. How do I do this?
> This is in a 12VDC circuit.
>
> Thanks!
>

matthewuw wrote:
> Here is the application:
>
> I have a momentary switch. When I press it, I want to switch something
> on (light bulb) and have it stay on even though momentary switch was
> released. maybe 500 mA draw.
>
> When I press it again, it turns the light bulb off. How do I do this?
> This is in a 12VDC circuit.
>
> Thanks!
>

There are a number of ways to do this. Do you want
to learn, or are you just interested in having
a circuit that will do it?

Ed

Will in the end, I need a circuit to do this. But I do want to learn.
What I asked for is actually only part of the functionality, but I see
it as a building block to start with and was hoping I might figure the
rest out on my own.

Well a push-on push-off switch isn't really momentary. It feels like a
momentary switch, but doesn't function like one. I have to use a
momentary switch, no option because or existing hardware.

Well a push-on push-off switch isn't really momentary. It feels like a
momentary switch, but doesn't function like one. I have to use a
momentary switch, no option because of existing hardware.

"matthewuw" <(E-Mail Removed)> wrote:

>Here is the application:
>
>I have a momentary switch. When I press it, I want to switch something
>on (light bulb) and have it stay on even though momentary switch was
>released. maybe 500 mA draw.
>
>When I press it again, it turns the light bulb off. How do I do this?
>This is in a 12VDC circuit.
>
>Thanks!

This should do it.
http://www.terrypin.dial.pipex.com/I...Momentary1.gif

There are many circuits for a 'toggle' or flip-flop, but that's the
simplest/cheapest I know of.

--
Terry Pinnell
Hobbyist, West Sussex, UK

Terry Pinnell wrote:
> "matthewuw" <(E-Mail Removed)> wrote:
>
>
>>Here is the application:
>>
>>I have a momentary switch. When I press it, I want to switch something
>>on (light bulb) and have it stay on even though momentary switch was
>>released. maybe 500 mA draw.
>>
>>When I press it again, it turns the light bulb off. How do I do this?
>>This is in a 12VDC circuit.
>>
>>Thanks!
>
>
> This should do it.
> http://www.terrypin.dial.pipex.com/I...Momentary1.gif
>
> There are many circuits for a 'toggle' or flip-flop, but that's the
> simplest/cheapest I know of.
>

Did you simulate that?

"matthewuw" <(E-Mail Removed)> wrote in news:1129097288.402163.260420
@o13g2000cwo.googlegroups.com:

> Here is the application:
>
> I have a momentary switch. When I press it, I want to switch something
> on (light bulb) and have it stay on even though momentary switch was
> released. maybe 500 mA draw.
>
> When I press it again, it turns the light bulb off. How do I do this?
> This is in a 12VDC circuit.
>
> Thanks!
>


I've tried this and it works. Simple and cheap. Sub in a 12vdc supply and a
12v relay.

http://beradio.com/news/radio_pushonpushoff_switch_2/

> Here is the application:
>
> I have a momentary switch. When I press it, I want to switch something
> on (light bulb) and have it stay on even though momentary switch was
> released. maybe 500 mA draw.
>
> When I press it again, it turns the light bulb off. How do I do this?
> This is in a 12VDC circuit.

You can use a miniature SCR bistable:
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