Post by thread:toggle switch circuit to turn a motor ON/OFF

'toggle switch circuit to turn a motor ON/OFF'

What's the application?

What voltage range power supply have you got available?

A classic 2 transistor bistable with steering diodes will probably do well

enough. 2 transistors and some diodes. Or you could use relays

But if you are happy to use a single IC, and operating voltage can be 3 to

15 volts with some CMOS logic families, then a single JK flipflop will do

exactly what you want. You'll need to debounce the switch with an RC filter

and you may want a startup reset circuit (one R one C) to clear the JK at

startup.

Connection:

J = high

K = high

Output from Q

Input = pulse to Clock.

Q will toggle.

This will run over a wide voltage range using a simple zener power supply.

Add a transistor driver for the motor. Swap from Q to Qbar if needs be to

get polarity correct. Beware of motor noise switching the circuit.

        RM

{Original Message removed}
I have seen mechanical switches that perfom this function, keep searching!

John Ferrell

http://DixieNC.US

{Original Message removed}
John Waters wrote:

> I need to turn ON or OFF a small 12V d.c. motor using a micro-switch,

> but

> the requirement is, the micro-switch must be operating like a toggle

> switch,

>

> I know a micro-switch alone will not be able to do this, I may need

> some

> relays or other components working together to achieve this, but I

> don't

> want complicated circuits that require a stable power supply,

The alternative with relays is a lot more clunky and complicated, especially

when considering debounce issues.

> I just want to

> use some simple passive components (and relays) to do this.

You are being silly.  You've got 12V, so a 7805 5V regulator and a couple of

caps will make a nice stable 5V power supply.  A PIC 10F200 can sense the

microswitch, perform the debouncing and toggle logic, and turn on the motor

accordingly.  The PIC can directly drive a IRFU3706 N channel FET low side

switch to control the motor.  The only other part you need is a reverse

diode accross the motor.

All this will be smaller, cheaper, more reliable, and take less power than

some relay logic.

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