Is this a Varistor or what ?

Thread Starter

paul1958

Joined Apr 30, 2021
8
I came across what Looks like a varistor. It definite loooks like a flat and round varistor and brown color. Ot can be wired across a 24 volt ac power supply to a small analogue relay and power it. The relay pulls less than 0.5 amps. The varistor is in series with the relay coil.

The resistance of the varistor is very very small too .But I believe AC varistor at no voltage has a very highresistance.

what could this be?
 

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BobaMosfet

Joined Jul 1, 2009
1,854
I came across what Looks like a varistor. It definite loooks like a flat and round varistor and brown color. Ot can be wired across a 24 volt ac power supply to a small analogue relay and power it. The relay pulls less than 0.5 amps. The varistor is in series with the relay coil.

The resistance of the varistor is very very small too .But I believe AC varistor at no voltage has a very highresistance.

what could this be?
@paul1958
That is a thermistor (either PTC or NTC), made by Littlefuse, Originally by RayChem (their logo).

That is a hold at 1.10A - It's ID is: X110 - You *might* find an obsolete datasheet for "RUX110"...
 

MisterBill2

Joined Jan 23, 2018
9,308
There are devices made and sold to protect circuits from overloads that are PTC devices. They do increase resistance as they heat and the resistance change is not linear. If the thing measures a low resistance that is one possibility. OR it may be a failed varistor that has protected something from a surge and become permanently conductive.
 

Thread Starter

paul1958

Joined Apr 30, 2021
8
Sincere thanks again. What is the meaning of Hold 1.10. What is this used for. To increase resistance as it heats up. ?
 

Thread Starter

paul1958

Joined Apr 30, 2021
8
@paul1958
That is a thermistor (either PTC or NTC), made by Littlefuse, Originally by RayChem (their logo).

That is a hold at 1.10A - It's ID is: X110 - You *might* find an obsolete datasheet for "RUX110"...
Sincere thanks.

What is the meaning of 1.10? What are these used for?
Mis this supposed to I crese resistance as it heats up ? Thank you again ?
 

Ian0

Joined Aug 7, 2020
3,281
Thank you much. This was great help. Can we use PPTC on AC circuits. Because the maximum voltage is given as DC volts..
Yes, provided you don't exceed the peak voltage rating.
Really - DON'T exceed the peak voltage rating because they start to crackle and catch fire.
 
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