Testing The green lab kit transformer
To check the windings:.
|From Pin 1 to Pin 2
|From Pin 1 to Pin 3
|From Pin 1 to Pin 4
|From Pin 1 to Pin 6
|From Pin 4 to Pin 5
|From Pin 6 to Pin 7
- If the tests above are good, Apply 10Vpp at 1kHz to Pin 1 with Pin 3 connected to the generator ground
- Measure V from Pin 2 to Pin 3 using the same ground point (should be about 5Vpp)
- Measure V from Pin 4 to Pin 5 (should be about 9.8Vpp)
- Measure V from Pin 6 to Pin 7 (should be about 9.8Vpp)
- NOTE: A bad cable can make a circuit act as if the transformer has failed.
If you are having strange problems with your transformer...
- check your cables to make sure that they all have good grounds
- The scope Ch1, CH2, and function generator all have a common ground.
The common ground can hide a bad cable ground because the other cables provide a ground path.
The ground connection fails when you go through a transformer because the primary and secondary windings are isolated from each other.
If you seem to have a signal on the secondary until you connect all of the cable grounds, one of the cables is bad.
- The ohm meter can check for a broken ground in a cable.
- If the bad connection is intermittent, it can be very difficult to find.