Slightly shonky voltage probe
Added 2023-03-24 23:14:32 +0000 UTCI promise, this is the last vehicular themed video for a while.
It's a low voltage probe with built in digital voltage meter, that could be used for many applications and not just automotive.
I get the feeling the circuitry may be based around either a dedicated meter chip, or a microcontroller mass programmed for this application. It's pleasingly minimalist, but astonishingly accurate. I tested it with a Fluke meter as a reference.
I reckon the mystery diode is to prevent the regulator being reverse biased by the tiny leakage current via the sense resistor network if the probe is applied to the wrong polarity.
https://www.youtube.com/watch?v=f7xBeN-wdj0
Comments
I think it's just a slight mark from manufacturing.
Big Clive
2023-03-28 17:50:52 +0000 UTCPossible reason for the diode: I know some three terminal regulator chips can be destroyed if the output pin is at a higher voltage than the input pin. Protection from backfeeding?
HarveyB
2023-03-28 06:56:56 +0000 UTCCool little tool. Did the "meter chip" have a whacking great crack on the left hand side of the package?
Jon Knight
2023-03-26 20:53:57 +0000 UTC
