question about a power switch

Thread Starter

theyikes

Joined Aug 27, 2012
10
Hi! Can anyone help me out?. I need to replace a power switch, it's not a simple on off switch, it's the kind of switch you have to hold down for a few seconds to turn it on or off. Does anyone know what they are called?
 

BobTPH

Joined Jun 5, 2013
6,076
Normally, that would be an ordinary pushbutton, and the circuit would implement the delayed turn on.

Are you sure the delay is in the switch? I have never heard if that.

Post a picture showing any markings in the switch.
 

Thread Starter

theyikes

Joined Aug 27, 2012
10
Wow thanks for the prompt reply guys! I can't post a picture of the original switch as it got damaged and lost. It's for an electric scooter. Is there a simple push on push off switch. I't got to be simple, it's kind of the reset button on a modem/router. If that makes sense?
 

djsfantasi

Joined Apr 11, 2010
8,661
It could be a latching pushbutton if it’s not a normal pushbutton.

How many wires connected to it? If only two, try manually connecting them briefly and see if it starts. Then, repeat but hold them together for a few seconds. If the scooter starts then stops when you separate the wires, the old switch was a latching type. If it continues to run, then the switch was a normal pushbutton. If there’s more than two wires, you can’t use this simple test.
 

Thread Starter

theyikes

Joined Aug 27, 2012
10
I tried connecting the two pins a week ago and it works fine. Is this making sense to you guys because I'm confused!!!!
 

djsfantasi

Joined Apr 11, 2010
8,661
I tried connecting the two pins a week ago and it works fine. Is this making sense to you guys because I'm confused!!!!
Yes, but what happens when you disconnect the pins? The behavior will tell us what type of switch to look for. There are different types.

It makes sense to me so far…
 

djsfantasi

Joined Apr 11, 2010
8,661
would it be a latching switch?
No. That indicates a normal pushbutton switch. Now you need to determine the current the switch needs to handle. Place a resistor between the two wires and measure the voltage across it. That and Ohms law will give you the current. The resistor may get hot and burn up if it’s too small. Start with a 1W 1k resistor. If it’s too small, the resistor will act like a fuse.
 

Thread Starter

theyikes

Joined Aug 27, 2012
10
all i know is it's 12v. I spotted the latching switch too but i wasn't too sure. Ohm's law is a bit beyond my purview. It worked when i connected it with a single strand or copper wire..... not sure if that make a difference.
 

djsfantasi

Joined Apr 11, 2010
8,661
all i know is it's 12v. I spotted the latching switch too but i wasn't too sure. Ohm's law is a bit beyond my purview. It worked when i connected it with a single strand or copper wire..... not sure if that make a difference.
You could use the technique of getting a switch roughly the same size of the old one and preparing yourself for the possibility it will burn out. But, since it appears that a momentary switch is all that is needed, it’s probably only carrying a signal current. And your likely to succeed.
 

Thread Starter

theyikes

Joined Aug 27, 2012
10
I think I'll go with the latching switch, i did a bit or reading up and it sounds like what I'm looking for. Thanks a million for your help. I wish i had half the knowledge you have with regard to these matters. djsfantasi. You rule!!
 

djsfantasi

Joined Apr 11, 2010
8,661
I think I'll go with the latching switch, i did a bit or reading up and it sounds like what I'm looking for. Thanks a million for your help. I wish i had half the knowledge you have with regard to these matters. djsfantasi. You rule!!
A latching switch will require you to press it 2-3 times before it will shut off. You need a momentary switch.
 

djsfantasi

Joined Apr 11, 2010
8,661
More information..,

When you connect the pins and disconnect them after a short delay, the pushbutton sends a short pulse to the controller.

The scooter stays on even though the wires are no longer connected.

To turn the scooter off, you connect and disconnect the pins agsin. The scooter sees a second short pulse and turns the scooter off.

A latching switch connects the pins the first time you press it and disconnects them on the second press. In order to see a second pulse, you have to push the button three times. Once to disconnect the pins, once to create a second pulse and once to finish the second pulse.

I don’t think that’s what you want.
 

MaxHeadRoom

Joined Jul 18, 2013
26,277
I doubt it is the switch that produces the delay, it is usually a normally open PB, and the delay is a function of what ever it is connected to, IOW, it doesn't recognize a non-delayed operation of the P.B.
The control itself exercises a delay from the continued push operation.
 

djsfantasi

Joined Apr 11, 2010
8,661
I doubt it is the switch that produces the delay, it is usually a normally open PB, and the delay is a function of what ever it is connected to, IOW, it doesn't recognize a non-delayed operation of the P.B.
The control itself exercises a delay from the continued push operation.
But how does it determine when to power off? The TS description indicates that it’s looking for a press of the pushbutton (i.e. a rising edge) to turn it off. A trailing edge doesn’t do it; the scooter remains on in that case. A latching switch wouldn’t produce a rising edge. The operator would have to press a latching switch at least twice.

I didn’t intend to imply a specific delay. Just that a momentary pushbutton was necessary. I agree that any delays are processed by the controller and not the pushbutton as long as a momentary signal was received.
 
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