3 ms·
Precise analog designs are tuned with provable error bounds. Actually, a digital potentiometer is likely used today to tune extremely tight tolerances. So a bi
by dragontamer 2y ago
Precise analog designs are tuned with provable error bounds.
Actually, a digital potentiometer is likely used today to tune extremely tight tolerances. So a bit of digital technique but overall it's analog (since digital pots are just turning analog resistors on/off with switches)
You buy 5% accurate components everywhere then just trim the errors down to 0.01%. Not easy per se, but 99.99% accuracy is doable at the student level with the right designs.
Professional level precision analog designs are the 7+ digit multimeters (99.99999% accuracy). Yes, built out of just 1% accurate parts.
If you need matching pairs, they make specially matched resistor chips or whatever.
--------
The concepts aren't hard btw though maybe slightly out of date. The book Art of Electronics analyzes a 7+ digit accurate multimeter design from Agilent or something.
Instead of using an analog pot to tune, today you'd use a digital pot. Otherwise, I'm pretty sure the overall analysis and technique holds in today's electronics market.
- lbourdages 2y agoInteresting. Would that be doable at a VLSI scale? I imagine that for large scale analog computers (like, neural networks) all these trimpots would become a challenge...
- dragontamer 2y agoTrue. VLSI does have techniques though. A clocked capacitor can sorta-kinda act as a trimpot if you calibrate the clock for example. And capacitors and clocks are more amicable to VLSI.