Need help identifying a power regulator

[yerawizardharry]

I have one of the below regulators that i used with a variable power supply with a 5.5mm plug and i need to get another one, unfortunately i do not have the skills to build one myself and i am having trouble sourcing one.


Can anyone tell me what i should be looking for as a replacement?

Thanks

 

[kpatz]

I don't see a regulator at all, just a circuit with a 15-ohm resistor, LED and that blue thing that looks a bit like a varistor (surge protector).

What is its application? And what voltage do you put in and what do you get out?

 

[yerawizardharry]

I got it in an electroplating kit years ago, it works as a cut out circuit, when the voltage is too high the led flashes. I used it with 1.5-9 volt via a variable power supply that plugs into it with a 5.5mm plug.

Any idea where i could get a replacement?

Thanks for your help.

 

[davenn]

it works as a cut out circuit, when the voltage is too high the led flashes

what do you mean by that ?
you have already said you are only using 1.5 - 9V ... it cant get higher than 9V

there's only 3 components in it

so what specifically is wrong with it ?

do you have a multimeter to test the resistor ?

Dave

 

[yerawizardharry]

About tree fiddy.

 

[(*steve*)]

About tree fiddy.

For those of you without access to the special google translate service, the above statement can be translated roughly as:

There is nothing wrong with it.

I showed my father how to electroplate some stuff with it and now he wants one, but i have no idea where to buy one as i don't know technically what it is called.

If you select a voltage too high for the area to be plated the led will flash. Or if the item to be plated makes contact with the anodes then the led will flash. If there is a short circuit between the anode bar and cathode bar it will flash. It works as a fault finder and cuts out the circuit.

edit, and I have divined this:

 

[kpatz]

The key seems to lie in that blue part. Sounds to me like it is normally closed and it opens when there is a fault, and then the current passes through the LED and makes it light up.

Maybe it's a polyfuse, also known as a PTC thermistor.

 

[davenn]

Maybe it's a polyfuse, also known as a PTC thermistor.

Makes sense, its resistance increases with more current so current takes easier path through the LED

Dae

 

[yerawizardharry]

Would it be correct to assume that if it is a thermistor then the device would only be good as a circuit breaker / fault finder for a few uses and then be deemed unreliable?

 

[(*steve*)]

The risk is that if it is a PTC that eventually (probably quite quickly) the LED is going to be damaged or destroyed. This will mean that overloads are no longer indicated, however the circuit will continue to operate.

The polyfuse (if that's what it is) may have a limited lifetime, and that will depend a lot on how much of an overload it gets.

 

[yerawizardharry]

The risk is that if it is a PTC that eventually (probably quite quickly) the LED is going to be damaged or destroyed. This will mean that overloads are no longer indicated, however the circuit will continue to operate.

The polyfuse (if that's what it is) may have a limited lifetime, and that will depend a lot on how much of an overload it gets.

Even if the maximum voltage does not exceed 12v?

 

[(*steve*)]

Possibly. It depends on the rating of the polyfuse (if it's a polyfuse).

What's the value of that other power resistor? And what is the load again? (I'll go back and check this, but if you haven't mentioned it, maybe you can tell us now).

 

[jpanhalt]

Would it be correct to assume that if it is a thermistor then the device would only be good as a circuit breaker / fault finder for a few uses and then be deemed unreliable?

Neither Vishay nor Murata give any specification related to the number of resets. Presumably it is large, unless the over-current situation was severe enough to actually damage the device.

John

 

[(*steve*)]

OK, so it's designed for 5V. The thing that looks like a LED is possibly a "flashing LED" designed to operate from around 5V.

If you operated this from 12V and drew too much current, tripping the polyfuse, you might kill the LED and possibly damage the polyfuse (*if* it's a polyfuse).

The LED if it failed would not exhibit any obvious signs (other than not working).

I'm not sure of the failure mode of polyfuses. I don't know if they can fail but still appear "normal"