Find the Value of Burnt Resistor by Four Simple Methods
In case of troubleshooting, repairing and designing electric and electronics circuits or damaged circuit broads, we may face this issue where we need to replace the damaged capacitor, diode, resistors etc. In case of resistor, we can find the values of burnt resistors by these four handy methods stated below.
- Scarp the outer coating.
- Clean the burnt section of the resistor.
- Measure resistance from one end of the resistor to the damaged section.
- Again measure the resistance from damaged section to the other end of the resistor.
- Add these two value f resistances.
- This is the approximate value of burnt resistor.
- Just add a small value of resistance for damaged section i.e., suppose the value of burnt resistor was 1k Ω, but you got 970 Ω. So just add 30 Ω, and you will have 1k Ω.
Also Read: How to check a Capacitor by 6 Simple Methods
This method can also be used for finding the value of burnt resistor(s) (also, may be applied on connected resistors in the circuit) in case if you don’t know about Resistance Color Coding.
- Connect resistor to multimeter and measure voltage drop across the burnt resistor.
- Now measure the current flowing into the resistor.
- Multiply both values and you will get the wattage of Resistor (As P = VI i.e. Ohm’s law).
- This wattage must be less than the wattage of the resistor being replaced.
This method could be used better if you know the expected output voltage of the circuit and you have a set of resistors of the same wattage as burnt resistor. Perform this method if you don’t know the value of resistor.
- Start with a high value of resistance and temporarily connect this resistor instead of burnt resistor.
- Measure the expected output voltage of the circuit. If you obtained same voltage as expected voltage then you have done.
- If you don’t know about the expected voltage, then keep reducing the value of resistor until you satisfy with the work of circuit for which purpose it was designed for.
Related Post: How to Test a Relay? Checking SSR & Coil Relays
Another method which is not always the case is that the value of resistors are already printed on the PCB. In case of burnt resistor, just look the printed circuit board (PCB) and look for the value of resistor printed on it. If not, you may follow above methods (1-3) instead.
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Let us know in the comment below if you know an additional method to find the value of burnt resistors.
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