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How to use low voltage switch for 110V circuit

mentalward

May 29, 2024
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My apologies if I didn't post this in the right thread.

I have a pressure switch, and want to use it to turn on/off a 110V extension cord. I feel like an idiot for asking because it seems like such a simple task, but so far every answer I've seen is too technical for me to understand.

I can blow into the pressure switch and verify that the switch is closing, and I have a 110v source. It seems like a relay would do the trick, but everything I've seen implies that it takes a low voltage source to trigger the relay, and I'm hoping to avoid that.

Thanks.pressure switch.png
 

Bluejets

Oct 5, 2014
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want to use it to turn on/off a 110V extension cord
but everything I've seen implies that it takes a low voltage source to trigger the relay,
A quick check on a spec sheet (which you should have supplied to save us the trouble of looking for it) shows they are indeed a low voltage low current sensor.

In that instance, a relay operating from low voltage would be required.

You also say "110v extension lead" as a load...........you also need to know the load current to select the correct relay for the job.
Manufacturer suggests solid state relay.
Mostly they will recommend these as coil induction effect of standard relay/contactors can have effect on the sensor.
 

danadak

Feb 19, 2021
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"Normally" one wants an isolated interface, that is AC line V can never get to the
contacts of the pressure switch or the fluid stream for human safety considerations.

One could use a wireless approach, switching on battery power to the remote
that operates the power relay. Or just use contacts on pressure switch in parallel
with the remote on button. One would want remote to be non latching possibly.


Alternatively one can use LED on AC side illuminating solar cell on pressure sensor side
to generate some power to allow pressure sensor to provide a switched V to a SSR,
to meet its turn on requirements. Or use a transformer driven by AC side to generate
circuit operating V on the pressure sensor side. Or an isolated power supply module
to gen the switched drive V.


Regards, Dana.
 

bidrohini

Feb 1, 2023
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Feb 1, 2023
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What is the load that you want to run? A motor? If yes, this may help:
 

AnalogKid

Jun 10, 2015
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it takes a low voltage source to trigger the relay, and I'm hoping to avoid that.
Too bad. The switch is rated for a max. of 30 V, so you will need a low voltage supply. Simple and cheap - an old USB wall wart / phone charger / camera charger / etc. That, plus a solid state relay rated for at least 50% more than your 110 V load current. Most SSR's have a current-limiting input so you do not need an external resistor.

DC output wall wart >> switch >> SSR.

ak
 
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