DC insulation resistance tester

[sivaprasadgnair]

I want to make an insulation resistance tester for 320V DC.Can any one guide me to make an idle circuit for this.

What is the basic principle behind insulation resistance testing.

 

[DeepOne]

my old project, 500V DC insulation tester. Useful thing.

 

[sivaprasadgnair]

thanks dear.can you please explain me how it measure insulation resistance, i mean the principle of insulation measurement.

 

[DeepOne]

nothing especial, it utilise usual Ohms law )
R = U/I

 

[crutschow]

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What is the basic principle behind insulation resistance testing.

Apply a high voltage to the insulation and measure the (very) small current that flows. Since normal insulation resistance is so high. you can place a large resistor in series (such as the 10MΩ input resistance of a typical digital meter) and measure the voltage across the resistor. From that and the applied voltage you can calculate the insulation resistance.

 

[chuckey]

And take suitable precautions against your device under test breaking down and exposing your circuit to the full applied high voltage.
Frank