Join us on Wednesday 17 July 2019 at noon Pacific for the Low-Level Analog Measurement Hack Chat with Chris Gammell!
A lot of electronics enthusiasts gravitate to the digital side of the hobby, at least at first. It’s understandable – an Arduino, a few jumpers, and a bit of code can accomplish a lot. But in the final analysis, digital circuits are just analog circuits with the mystery abstracted away, and understanding the analog side opens up a fascinating window on the world of electronics.
Chris Gammell is well-known around hacker circles thanks to his Amp Hour Podcast with Dave Jones, his KiCad tutorials, and his general hacker chops. He’s also got a thing for the analog world, and wants to share some of the tips and tricks he’s developed over his two decades as an electrical engineer. In the next Hack Chat, we’ll be joining Chris down in the weeds to learn the ins and outs of low-level analog measurements. Join us with your questions and insights, or just come along to peel back some of the mysteries of the analog world.
Our Hack Chats are live community events in the Hackaday.io Hack Chat group messaging. This week we’ll be sitting down on Wednesday July 17 at 12:00 PM Pacific time. If time zones have got you down, we have a handy time zone converter.
Click that speech bubble to the right, and you’ll be taken directly to the Hack Chat group on Hackaday.io. You don’t have to wait until Wednesday; join whenever you want and you can see what the community is talking about.
I miss my old Analog meter… We had good times together. It was rather, resistant, sometimes though. *Rolls laughing*
I miss my AVO meters too .. lost them in a house move along with an old home made valve o-scope. keep resisting the urge to buy one on ebay because nostalgia.
Relevant: An excellent book by Keithley, ranking right up there with Horowitz & Hill, is Low Level Measurements, now available gratis at https://download.tek.com/document/LowLevelHandbook_7Ed.pdf (direct link to PDF, sorry).
(yes, the venerable Keithley got bought by Tek, which got sucked up by Danaher via a couple of other deals, which spit out Fortive to rule them all. It’s ugly blood-sucking business deals that do no good for the pawn companies like Keithley, but it’s still a solid book. Highly recommended, especially for the price)
I have a pretty good collection of old meters. For sensitive DC voltage measurements there is the potentiometer, standard cell, and mirror galvanometer. Three decent sized boxes used to be required to read dc voltages. 4 if you count the battery to light up the lamp in the galvanometer.
If you don’t mind loading the DUT down a bit, the old Weston voltmeters were interesting. They used electromagnets for the stator so they respond to both AC and DC. Kind of an interesting trick in the days before semiconductor diodes.
The down side of this old stuff is each meter covers perhaps 2 ranges and is in a rather large and heavy wooden box. Replicating the functions of a free HF DVM is just about impossible and coming close would require a truckload of boxes. The gem in the collection is the 326 voltmeter, this is about a foot square and goes from 0 to 75 or 0 to 150 volts AC or DC.