Timeline for What does the multimeter dial do internally?
Current License: CC BY-SA 4.0
13 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Jun 26, 2023 at 4:21 | comment | added | Hearth | @slebetman I would expect solid-state relays would be better choices, given the potentially high voltages involved. | |
| Jun 26, 2023 at 4:03 | comment | added | slebetman | @JerryCoffin You're not replacing that wiper with the A2D, you're replacing it with an analog multiplexer. Those things aren't exactly cheap especially if you want good quality one for your measurements. The other parts of the circuits would still be there because you'd still need to switch when the range changes to maintain your precision. | |
| Jul 22, 2019 at 0:16 | vote | accept | S. Rotos | ||
| Jul 7, 2019 at 14:44 | comment | added | Nick Alexeev | Another similar picture of the tracks under the dial can be found here. Different DMM, same idea. | |
| Jul 6, 2019 at 17:00 | comment | added | Hearth | @JerryCoffin I wonder. Relays aren't exactly the cheapest things either, and there's additional software complexity to do the automatic switching as well as the hardware bit. Consider the $5-$10 meters you find on ebay; I've never seen one of those that's got autoranging of any sort, and those switches are probably really cheap if you have the injection molding machine to make them. | |
| Jul 6, 2019 at 15:32 | comment | added | Jerry Coffin | "A meter that auto-ranges is more expensive than one that doesn't due to the need for additional hardware to detect when it's over-range and perform the switching." I wonder whether that's still really true.That big, mulicontact rotary switch costs a fair amount of money. A coarse A2D plus a comparator might well be cheaper. It wouldn't surprised if the current design continues more through inertia than real cost savings. | |
| Jul 5, 2019 at 15:18 | history | edited | Hearth | CC BY-SA 4.0 |
added 285 characters in body
|
| Jul 5, 2019 at 14:46 | comment | added | Hearth | @Transistor Ah, the march of progress! | |
| Jul 5, 2019 at 14:45 | comment | added | Transistor | I only know that much because I built a multimeter using one about 40 years ago. They seem to be pretty much the same devices in the €5 meters available in the supermarket these days. Mine cost me a lot of pocket money at the time. | |
| Jul 5, 2019 at 13:27 | history | edited | Hearth | CC BY-SA 4.0 |
per @Transistor's comment
|
| Jul 5, 2019 at 13:25 | comment | added | Hearth | @Transistor I used that value just as an example, as I don't know what a typical range would be. Good point about it being the lowest range, though. | |
| Jul 5, 2019 at 13:21 | comment | added | Transistor | "Internally, the meter can only measure voltages from, say, -1V to +1V." It is more than likely the lowest DC V range. ±199.9 mV on the basic digital meters. "... so the multimeter chip can digitally multiply that voltage back up ..." It's easier than that; one pole of the switch selects the relevant decimal point. No multiplication required. | |
| Jul 5, 2019 at 13:06 | history | answered | Hearth | CC BY-SA 4.0 |