WARNING

Valve equipment uses high voltages. Most early mains radios and televisions have a live chassis, so be bloody careful. I use an isolating transformer which not only helps to protect me but is necessary if you're going to connect earthed test gear to the chassis of the equipment. If you don't have an isolating transformer, make sure that the chassis is connected to the mains neutral. Don't go killing yourself, you might regret it later.

This voltmeter has a very high input impedance, something in the region of 10 meg. More coming soon...