How Safe is a Homemade Isolation Transformer?
Some people will claim that because it is homemade from salvaged parts, it *cannot* be as safe as a commercial unit. Keep in mind that I am not talking about using something that has been rusting away in a damp basement for 20 years. The power transformers from tube-type TVs or audio amplifiers must have been designed with isolation requirements in mind to obtain regulatory approval in the first place since they are used in equipment where the user may come in contact with metal parts. Also, the use of an isolation transformer is no excuse to ignore the other aspects of safe troubleshooting. It is easy to test for AC and DC leakage – and this should be done – to be sure that your transformers are in good condition. With two transformers, the probability of a failure is even smaller – 1/(P*P). Personally, I would trust the homemade transformer over a cheap import any day! Variable Autotransformers A variable autotransformer (Variac is the trade-name of one popular brand) enable the AC i
