In electronic devices:

Lowest level of the power transformer is found in electronic equipment like television sets, ham radios, and home computers.

Most solid state devices use low voltages, varying from about 5 V up to 50 V. This equipment requires step down power transformers in the power supplies of it. Solid state equipment usually consumes relatively little power, so the transformers are normally not very bulky. The exception is the high powered audio frequency or radio frequency amplifiers, whose transistors can demand over 1000 watts (1 kW) in some of the cases. At 12 V, this translates to 90 A or more.

Television sets have a cathode ray tube which requires several hundred volts. This can be derived by using a step up transformer in power supply. Such transformers do not have to supply a lot of current, though, so they are not very large or heavy. Another type of device which requires rather high voltage is a ham radio amplifier having vacuum tubes. This type of an amplifier requires 2 kV to 5 kV.

Any voltage over12 V should be treated with respect. The voltages in televisions and ham radios are very dangerous, even after the equipment has been switched off.