13-04-2013, 10:45 PM
OK, I couldn't resist ordering a couple of these:
http://www.ebay.co.uk/itm/New-5-Digit-0-...uipment_ET&hash=item27cff14841
I've no idea how good these will be, but for less than a fiver each, it's got to be worth a go. I have a decent 5-digit DVM here that I can compare them to when they arrive...
These are interesting because 5-digit ADC/driver ICs are rare and expensive. I'm not sure which chip these use - perhaps it's a custom microcontroller instead. Just about every digit panel meter is 3.5 digits, based on the 7106 or 7107 for LCD or LED respectively. These chips are great, and have been second-sourced by manufacturers like Maxim over the years, but there are times when readings that only go to 1.999 are a bit restricting.
For example, the Thulby-Thandar PL series bench power supplies had meters that could go to 3.999. The metering is why these supplies were so popular. The IC they used went obsolete in the late 1980s, so they redesigned it using another ADC and a PIC microcontroller (I have examples of both here). Then a newer version came out with standard 1.999 displays (LCD as well), but this meant the voltage resolution was now 100mV instead of 10 (because the supplies went to 30V). I remember how people reacted to these at the place I worked at the time. No idea what newer models use internally, but the resolution is back to 10mV now.
Anyway, I'm waffling. If these 5 digit modules are any good, I'll let you all know (once I've snapped up a few more
)
Cheers,
Mark
http://www.ebay.co.uk/itm/New-5-Digit-0-...uipment_ET&hash=item27cff14841
I've no idea how good these will be, but for less than a fiver each, it's got to be worth a go. I have a decent 5-digit DVM here that I can compare them to when they arrive...
These are interesting because 5-digit ADC/driver ICs are rare and expensive. I'm not sure which chip these use - perhaps it's a custom microcontroller instead. Just about every digit panel meter is 3.5 digits, based on the 7106 or 7107 for LCD or LED respectively. These chips are great, and have been second-sourced by manufacturers like Maxim over the years, but there are times when readings that only go to 1.999 are a bit restricting.
For example, the Thulby-Thandar PL series bench power supplies had meters that could go to 3.999. The metering is why these supplies were so popular. The IC they used went obsolete in the late 1980s, so they redesigned it using another ADC and a PIC microcontroller (I have examples of both here). Then a newer version came out with standard 1.999 displays (LCD as well), but this meant the voltage resolution was now 100mV instead of 10 (because the supplies went to 30V). I remember how people reacted to these at the place I worked at the time. No idea what newer models use internally, but the resolution is back to 10mV now.
Anyway, I'm waffling. If these 5 digit modules are any good, I'll let you all know (once I've snapped up a few more
)Cheers,
Mark
