/diy/ - Do It Yourself

>>2406892
Ok here's a design for the mΩmeter, one that uses the panel meter. But there are a few things I'm not too keen on. The two-op-amp differential amplifier instead of a 3-op-amp instrumentation amplifier circuit isn't wonderful, also the damn TL072s are causing me to put a zener there to keep in their common-mode-range. This will result in a 12V power supply with only the inner 4V being usable. Having to add a virtual ground circuit to bump the panel meter somewhere the op-amps can output to is equally shitty feeling. That BJT circuit should work for detecting overflows, and maybe that can be used to energise a relay to change the range.

But now I'm thinking about that MCP3911 I happen to have lying about...
A 14-pin micro isn't enough to multiplex a 5-digit display, nor is anything I have high enough accuracy to warrant such a treatment, but it certainly is tempting.