Method for "conditionning" a carbon resistor
by Jean-Louis Naudin

Created on 11-24-00 - JLN Labs - Last update 12-08-00

You will find below a method for building yourself a non-linear resistor with a common old carbon composite resistor. This component has some interesting characteristics such as a high resistance in DC and a low resistance at AC High Voltage ( >1KV )....

Material required :

Procedure :

  1. Connect one side of this brand new carbon resistor on the 0 Volt side and the other side at about 6 mm from the HV output so as to get a spark gap,
  2. Switch on the HV power supply and adjust the spark gap so as to get the max spark distance,
  3. You will observe that the yellow color bar will began progressively orange, this indicate the warm up of the resistor,
  4. You will notice that the spark will vanish after about 1 minutes,
  5. Switch off the power supply and check the value of this conditionned RLoad, the value must be now about 300 K... If this is not the case run the step 2 again,
  6. Your "conditionned resistor" is now ready to be used for your tests…

In the pictures below, I have used a 220K 1/2 carbon resistor for a demonstration purpose, but I recommend you to use a 100 Kohms 5 Watts carbon resistor for your testing.

The HV power supply arrangement used as the resistor conditionner

Above, you see that the resistor is made with carbon ( no wire )

The "conditionning process", you may notice the spark
and the change of the color bar of the resistor.

The pictures above see the change of the resistor value after the process

For more informations, you may write me directly at :

All informations in this page are published free and are intended for private/educational purposes and not for commercial applications

Disclaimer: The author assumes no liability for any incidental, consequential or other liability from the use of this information. All risks and damages, incidental or otherwise, arising from the use or misuse of the information contained herein are entirely the responsibility of the user. Although careful precaution has been taken in the preparation of this material, I assume no responsibility for omissions or errors in the diagrams or measurement datas published here.  

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