> -----Original Message-----
> From: Will Cooke via cctalk <cctalk@classiccmp.org>
> Sent: 26 November 2022 19:12
> To: Rob Jarratt via cctalk <cctalk@classiccmp.org>
> Cc: wrco...@wrcooke.net
> Subject: [cctalk] Re: Identifying a Failed Diode in a Rainbow H7842 Power
> Supply
>
>
> I'm not at all familiar with either this circuit or any of the mentioned
> diodes.
> However, I would point out that a diode's forward voltage drop varies with
> current through it. Usually, the datasheet will list the "max" forward drop,
> at
> the rated current and typically at the lowest rated temp (the drop decreases
> as temp rises.) So it is entirely possible that your tester is putting a
> very small
> current through a high-current diode and getting that 0.5V. It might be
> useful to feed it something close to its rated current and measure the drop
> for a more accurate estimate.
Thanks, I didn't know this, there is still so much I have to learn! I had
noticed that the datasheets say "max" forward voltage but wasn't sure of the
significance.
>
> Will
