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Is it possible to make a push switch latching without using a programmable IC?

I have a circuit with a 555 chip creating a square wave. I would like to add a push switch which when pressed once will turn the circuit on, then when pressed again will turn the circuit off.

Is it possible to do this without using a programmable IC? I was thinking of using an ATTINY85 but was wondering if there is an easier and more cost effective way.

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    \$\begingroup\$ If you use a micro like an ATtiny you can do away with the 555 and have the micro do both the latching and generate the square wave. \$\endgroup\$
    – GodJihyo
    Mar 31, 2023 at 14:21
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    \$\begingroup\$ How about a mechanical pushbutton switch that does exactly that? A "maintained' pushbutton switch - they are very common. Push once to turn on, push again to turn off. \$\endgroup\$ Mar 31, 2023 at 14:23
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    \$\begingroup\$ Another 555 could be used. There's a actual latch inside... \$\endgroup\$ Mar 31, 2023 at 14:30
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    \$\begingroup\$ Circuit as cheap as possible = one MCU to do everything. \$\endgroup\$
    – winny
    Mar 31, 2023 at 14:37
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    \$\begingroup\$ Yes. MCUs are getting cheaper and cheaper while ever so more versatile. Your 1.5 USD RP2040 could do the entire Apollo mission. \$\endgroup\$
    – winny
    Mar 31, 2023 at 14:39

2 Answers 2

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Plenty of options!

An OR IC, any 74x32 in this configuration:

schematic

simulate this circuit – Schematic created using CircuitLab

Or if you want it even more discreet, the classic BJT thyristor configuration, borrowed from here: Replace transistor-latch with thyristor: is my circuit correct?

enter image description here

Suggestion by Chris Knudsen, latching relay:

schematic

simulate this circuit

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    \$\begingroup\$ ...and the classic start-stop control switch using latching mechanical relays, or relay feedback. \$\endgroup\$ Mar 31, 2023 at 14:26
  • \$\begingroup\$ @ChrisKnudsen Classic! I'll add it. \$\endgroup\$
    – winny
    Mar 31, 2023 at 14:29
  • \$\begingroup\$ @winny Great thanks for you answer. The schematic above the "BJT thyristor configuration" has two switch. A trigger and reset. Is it possible to achieve the same outcome with only one switch. Thanks \$\endgroup\$ Mar 31, 2023 at 14:37
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    \$\begingroup\$ OK, so how is the OR circuit supposed to toggle? :^) \$\endgroup\$
    – Transistor
    Mar 31, 2023 at 16:42
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    \$\begingroup\$ @winny - The text says, " I would like to add a push switch which when pressed once will turn the circuit on, then when pressed again will turn the circuit off." \$\endgroup\$ Apr 3, 2023 at 16:05
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Nothing as simple as a 'self-locking, push-on / push-off switch'.

enter image description here

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