Calibration
Equipment Required
Oscilloscope
Distortion meter
4.5 digit battery powered multimeter
Calibration should be carried out after the instrument has been on for 1 hour.
Note:
If any work has been done to the output stage, VR32 and VR33 must be turned fully anti-
clockwise before switching on.
The available calibration points are:
Dial calibration, high frequency (5.0) end, 10k range - VR3
Dial calibration, low frequency end (.005) - VR2
Waveform symmetry, high frequency end of dial (5.0) - VR9
Waveform symmetry at the low frequency end of dial (.005) is affected by offset nulling of ICs 2 to 6,
see below.
Dial calibration 1M range - VC1
Dial calibration 100k range - VC2
Capacitance multiplier offset - VR16
Capacitance multiplier gain - VR15
DC offset of triangle amplifier - VR17
Sinewave distortion - VR18, VR19, VR22 and VR23
Sinewave dc offset - VR20
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