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- 1). Set up the signal generator to put out 1,000 Hz tone at a level compatible with your transformer's rated input.
- 2). Connect the output of the signal generator to the input of the transformer. If your signal generator cannot put out a sufficient output, apply the signal to the input of the amplifier stage before the transformer.
- 3). Connect the input to the transformer, be it directly out of the signal generator or at the output of another device, to the A channel input of the oscilloscope.
- 4). Connect the output of the transformer to the B channel input of the oscilloscope.
- 5). Set the oscilloscope to superimpose the two signals over each other. Use the A channel as a sync. Use the oscilloscope vertical controls to measure the two signals, and thus the loss or gain of the transformer. If there is no distortion, the two signals should be shaped exactly the same.
- 6). Vary the signal generator down to 20 Hz and observe the two signals on the scope. Compare the results with the frequency response specs of the transformer.
- 7). Run a frequency response curve. Set the signal generator in stages up to 20 KHz (20,000 Hz). Select the stages at random or per the specifications of the transformer. If in doubt, measure every 2 KHz (2,000 Hz, 4,000 Hz, 6,000 Hz, etc.) Watch the two signals and the differences between them, and compare them to the frequency response specifications of the transformer.
- 8). Turn down the intensity of the A trace on the scope and run your frequency response curve again. Look closely at the B trace for any juggling or flashing that would indicate instability or distortion at the same frequencies as your response curve. A good distortion specification is less than one percent total harmonic distortion.
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