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- 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 Burn 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.
This method also can be used for finding the value of resistors (Also, for connected resistors in the circuit) if you don’t know about Resistance Color Coding.
- Connect Resistor to Multimeter and measure voltage drop across Resistor.
- Now measure the current flowing into the resistor.
- Multiply both values and you will get the wattage of Resistor (As P = VI)
- This Wattage must be less than the wattage of the resistor being replaced
This method can be better used if you know the expected Output Voltage of the circuit and you have resistors set of 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 work of circuit for which purpose it was designed.