A popular electrical component used on many control circuits is the step-down transformer. It is the power source for a separate lower-voltage circuit which typically controls the operation of a system.
Checking the acidity and/or moisture content of refrigerant oil is one of the methods used to test if a refrigeration system is clean and uncontaminated. But how can you take an oil sample without an oil plug?
Today more and more systems are incorporating microprocessor controllers into their design. Troubleshooting the operation of these controllers can be a little tricky at times, but if broken down into sections it can be easier to handle.