Back in the early days of electricity, lab workers could measure electric current in a circuit using an ammeter (galvanometer) and voltage using a voltmeter. From there, they could calculate ...

All, I posted this at DIYMA, and didn't get too may helpful responses, so figured I'd ask the Hive Mind. Back in the '90s, I used to set amp gains by turning the level pot all the way up and then ...

If your goal is to save on electricity, you must first measure the ac current flowing through your appliances. The formula for power is the product of the ac line voltage and the measured current.