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Fig - 7 PCB

wise, set Sl to the nF position and apply power to the project. The display will light and within 2 seconds will reset to ".000." Rotate ZERO potentiometer R10 fully clockwise. The display will indicate a few picofarads (.003 to .030 nF). Slowly rotate the ZERO potentiometer counter-clockwise until the display reads ".001."

 

Rotate the control siightiy counterclockwise until it reads ".000." Connect a reference capacitor with a known value of 0.68-µF to the CXtermi- nals of the meter. The display will count up for about one-half second and stop at some value which is not critical at this time. Place Sl in the ~LF position.

 

The display will read a similar value, but will not appear to flicker. Finally, place a 5000-to-8000-RF capacitor across the CX terminals. Within a few seconds, the display will advance and the overrange LED's will cycle top on only, bottom on only, both on, both off, and repeat the sequence . The meter is now ready for calibration.