I suppose I can take credit for introducing the super awesome [Fran Blanche] to Hackaday’s very own crotchety old man and Commodore refugee [Bil Herd]. I therefore take complete responsibility for [Fran] and [Bil]’s Dinosaur Den, the new YouTube series they’re working on.
The highlight of this week’s episode is a very vintage Rubicon mirror galvanometer. This was one of the first ways to accurately measure voltage, and works kind of like a normal panel meter on steroids. In your bone stock panel meter, a small coil moves a needle to display whatever you’re measuring. In a mirror galvanometer, a coil twists a wire that is connected to a mirror. By shining a light on this mirror and having the reflected beam bounce around several other mirrors, the angle of the mirror controlled by the coil is greatly exaggerated, making for a very, very accurate measurement. It’s so sensitive the output of a lemon battery is off the scale, all from a time earlier than the two dinosaurs showing this tech off. Neat stuff.
One last thing. Because [Bil] and [Fran] are far too proud to sink to the level of so many YouTube channels, here’s the requisite, “like comment and subscribe” pitch you won’t hear them say. Oh, [Bil] knows the audio is screwed up in places. Be sure to comment on that.
A galvo is an ammeter, not a voltmeter.
Otherwise, this looks like a great start to a great series!
It needs volts volts to get the amps flowing and the coil has a fixed resistance value. The rest is jus tOhm’s Law.
Usually a voltmeter is an ammeter with a high-value resistor in series. Or a milli-amp meter, more specifically. An ammeter is a mA meter with a low-value shunt resistor in parallel. If it’s a uA meter, use a different resistor.
The actual movements used in analogue, moving-needle meters are usually just milliammeters, with whatever arrangement of stuff around them to make them fit the purpose.
Though, of course, you can’t have amps without volts. Volts are pushed, amps are pulled. In the case of this antique galvanometer type thing, I don’t know what it’s resistance is, and what it usually measures.
Oh, talking of instruments that surely must be obsolete by now, I remember losing a lot of points in a school entrance exam, for not having a clue what a “gold-leaf electroscope” was. I know now, I’ve made them since, but I think conflicting syllabusses put the exam question before the actual teaching..
The deflection force is directly related to the current flowing and only indirectly related to the voltage across the coil (via Ohms Law).
The unintentional reverb is *far* less annoying than the intentional music in the background.
Not entirely surprising after the annoying video in the background during the opening sequence.
I’m sorry, but there is no way I can put up with this for 60 minutes.
Hi, I just watched an episode of that Dinosaur Den and sadly I had to give it a thumb down because of a stated safety caution about drilling in FR4 laminate (Glass dust, and that you would need an environment with filters and fume cupboard, etc). After that I searched on Google for similar claims and I did not find anything (Like someone else who had commented on there, it was what made me alert of this). I live in an apartment as well, and like many of us in the society, so installing such things would be too pricey and the landlord would not like it either. I have a VERY strong interest in electronics and I watched it to get inspiration, I had bought a full electronics lab too with expensive instruments and want to fulfill this, so it is not very inspiring to see someone claim things like that person on the video did. I have talked to a friend who has an electronics interest (but is no longer doing it because of a loss of time), and he thinks it is a very strange claim! A painting mask would be enough for sure! I would like you to reply this message and give me feedback, I am disappointed and I want to feel I can continue with electronics. Tell me about your reaction about this, and strangely enough, I always seem to meet complete ignorance, I have gotten no answers ever. If I was Hackaday I would not support people claiming things like that.