EEVblog 1688 - Constant Current Circuit EXPLAINED + DEMO
Added 2025-05-27 08:47:46 +0000 UTCPre-release.
This turned out twice as logn as I thught it would be.
I wanted to include an LM317 battery charging demo but it was already too long.
Comments
Hey, does someone know how Dave created the program that did the math in his calculator watch. Did he use libs provided by the micro manufacturer? I have written lots of code but never anything like his calculator watch. Not intending to build one was just very curious.
Billy Martin
2025-09-24 05:16:34 +0000 UTCI have built up so many circuits based on the Fundamentals series, I agree with Marco, they cannot be too long.
Billy Martin
2025-09-21 19:15:16 +0000 UTCThank you for this (and so much else). Yes, unfortunately YT has become a wasteland for you creators and we consumers. Proud to support you here on Patreon and view you here and Odysee. I’ve been YT-free for over a year. Too many better options (including Nebula and others) to put up with YouslessTube.
Brian Deschene
2025-05-28 11:57:16 +0000 UTCAnother vital application of such circuits is in communications, particularly in high-noise environments, where these are called "current mode" communications, and are used by both digital and analog communications loops (where the loop itself provides much of the integrity), such as RS-485 (digital) and 4-20ma (analog). I was first exposed to these in the US Navy, where a ship can be viewed as a massive noise source that wants to destroy all local communications (and where nuclear weapon EMP is a concern). Since then, I worked with current-mode comms in many other high-reliability systems, including nuclear power plant instrumentation and controls, and aircraft and space instruments. The main downside of current-mode communications is the lower data rate, as rapid current switching demands an ever-increasing compliance voltage (and/or more copper), which creates its own issues unless the rate of current change is properly managed. However, a benefit is a reduction of conductors needed for shielding, as a twisted-pair can often provide all the immunity needed. When your systems must communicate in a very hostile world, current-mode communications can provide immense benefit.
BobC
2025-05-27 18:30:31 +0000 UTC
