Interesting Circuit From EDN to Measure 0 – 1000 Volts With a '555

EDN posted an interesting circuit to measure from 0 volts – 1000 volts with good resolution using the ever popular 555 chip and a single micro GPIO pin. Not that I have had much need to measure high DC voltages, but the idea is fantastic.

I'll leave the explanation of how it works to the article (linked above, PDF below). The circuit is dead simple (speaking of dead, be careful around high voltages), depending on the charging time of a capacitor. Complexity and component costs are low.

My favorite part of this circuit is the quote from the designer " and it never really over-ranges". It's so nice when you think you're dealing with a 1kv source but it's really 30kV - that way you don't have to worry about fuses or other anomalies.