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very low voltage relays

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Feb 6, 2022
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Hope this is the right area to post, so I'm no electronics expert and but can build a circuit on a breadboard etc

I have two muon detectors each powered by their own a 5 volt DC Supply

If a detector is activated then a LED flashes (briefly) i think the LED voltage is between 1.8 and 3.3 volts

So I'm trying to do two things and want know it its possible and then some pointers please

1 - When a detector is activated rather than powering the LED could it activate a relay (this then opens up possibilities for me),i assume i would need a very low voltage relay that's going to be quite responsive ?

2 - When both detectors are activated again activate a relay, from reading I may need an IC that will have the logic for two High Inputs (the detectors) and then an High Output for the relay

Kind Regards
John B


I don't know what a muon detector is ... and how important this is for the relay.
Also I don't understand how a (or two) detectors are related to LED and relays.
Also I don't know your circuit.

Also it's not clear what you mean by "low volt" relay.
Relays have coils tha need voltage to operate. Ac, DC, high voltage, low voltage, latching, monostable...
But relays have contacts. Some relay contacts are made to switch low voltage - they are designed for low thermocouple voltage.

If you are looking for relays .. I recommend to go to a distributor's web site and use the relay selection tool.
Also every relay manufacturer provides a lot of useful informations how to choose the best relay.

If you need more detailled informations I strongly recommend to
* focus on your problem
* draw a sketch



Sorry i was not clear

I guess the muon detector is not relevant, however its output is an LED that will flash sometimes

What I want to do is rather than have a an LED flash I want to connect a relay so I can control other things via the contacts

Does this make more sense

Kind Regards
John B

A little... but how long does the flash last for and how frequent are they?
Relays have a finite response time, they are partly mechanical so they won't respond quickly. It is very doubtful you will find a relay of any substantial size that will operate with the same voltage/current as an LED but it is a trivial task to use the LED voltage to operate a relay driver circuit, then you can use almost any relay. A relay driver may be nothing more than a resistor, a transistor and a diode.



thanks so the LED will flash say10 time per minute and each time the Led will be on for a second, reading your response I need to research relay driver circuits

Kind Regards
John B


As I understand you want to activate a relay (low voltage coil) instead of activating a LED.

We electronic designers use physical measures, mainly voltage and current.
So a standard LED needs about 2.2V and 20mA. I don't know if there us a relay that can work with 2.2V and 20mA (I leave it in you to do the search)
But it is sufficient to activate a transistor ... and the transistor can drive the relay. So there will be a solution.

There are two partners:
* the output of the detector
* the relay coil.

You need to know how much voltage and current the detector is able drive
And you need to know the relay's voltage and current specification.
... to say wheter you need a transistor or not.

Please mind: when you say "control other things" ... we don't know what this means. Thus we can not use this information to help you.
The more clear and detailed your information, the better we can help you.


A good all around relay for low to moderate current loads are SSR (Solid State
Relay). Available for both AC and DC loads. Many also have the advantage load is
galvanically isolated from control circuits. Small PCB mount, to terminal screw versions.

Regards, Dana.

Muon detector is basically a scintillation counter.
The little muon beasties streak through some kind of scintillator which I believe for muons is usually a large light proof tank of clear fluid, creating a very weak momentary flash of light. That is detected by a photomultiplier tube to create a short electrical pulse.
As this pulse comes out of an amplifier, and is of short duration, flashing a LED might just be possible, but operating a relay directly is not going to work too well.
The pulse really needs to first be increased in length with a monostable multivibrator, the output of which can then more easily power a relay or electromechanical counter.

If you just wish to count the pulses over time, which seems most likely, an electronic counter should more easily do the job directly from the photomultiplier tube.

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