Momentary contact switched to latched state on/off?

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SpaceDuck
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Momentary contact switched to latched state on/off?

Post by SpaceDuck »

I have some momentary contact pushbutton microswitches that are the perfect size and fit for my needs but my circuits should be using "regular on/off switches" instead. Did a lil searching on the web and it seems a common issue but so far I'm reading of multiple components being needed to accomplish this?

Would someone/anyone/you, care to share how this can be accomplished in the easiest manner?

Thanks in advance!
Duck Dodgers of the 24th and a half century!
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SpaceDuck
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Post by SpaceDuck »

Hmmm, stumped the electronic Gurus out there? :roll:
Duck Dodgers of the 24th and a half century!
jwrjr

Post by jwrjr »

That depends on whether the switch is directly controlling much power. If not, use a D-type flipflop wired to toggle (a 74hct74 should do well).
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SpaceDuck
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Post by SpaceDuck »

jwrjr wrote:That depends on whether the switch is directly controlling much power. If not, use a D-type flipflop wired to toggle (a 74hct74 should do well).
Under 12V?
Duck Dodgers of the 24th and a half century!
jwrjr

Post by jwrjr »

For 12v it would probably have to be a 4000-type D-type flipflop. I don't know what the part number would be. Just connect the /Q output to the D input, and connect the switch to the "clock" input. It will probably be necessary to connect the "clock" input to the power supply using a resistor (10k - 100k, value not critical) and to ground using a small capacitor (0.1uf is good). The reason for this is that mechanical switches' contacts "bounce" when you close the switch. The capacitor acts as a shock absorber. The resistor makes sure that the input is "high" until the switch pulls it down. Without the resistor the input floats, and you get a "maybe" Not good.
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SpaceDuck
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Post by SpaceDuck »

jwrjr wrote:For 12v it would probably have to be a 4000-type D-type flipflop. I don't know what the part number would be. Just connect the /Q output to the D input, and connect the switch to the "clock" input. It will probably be necessary to connect the "clock" input to the power supply using a resistor (10k - 100k, value not critical) and to ground using a small capacitor (0.1uf is good). The reason for this is that mechanical switches' contacts "bounce" when you close the switch. The capacitor acts as a shock absorber. The resistor makes sure that the input is "high" until the switch pulls it down. Without the resistor the input floats, and you get a "maybe" Not good.
You echoed what I've read elsewhere about the "bounce factor" of a momentary switch trigger. But so far, the "other" schematics which seem similar, use a transistor/s, several caps and more. I'm in absoluetly no position to "judge" their suggestions but like always I am looking for the tidiest/easiest way out of course! :P

You may recall, you've always stepped up to assist in my quandries though it was quite a while ago so I do once again thank you.

So, how many chocolate chip cookies might it take for you to transfer that into a working schematic and parts list for me? :oops:
Duck Dodgers of the 24th and a half century!
jwrjr

Post by jwrjr »

I will see what I can do. Stay tuned ...
jwrjr

Post by jwrjr »

Give me an address to send it to. I didn't make up a parts list as A. they are well identified on the schematic, B. with one exception are all non-critical, and C. all are as common as dirt. If you still need a list, tell me where you buy parts from and I will see about getting for you some part numbers.
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