vfd dmm - Page 1
Forum section: electronics / testgear

author: artag
author_rank: Super Contributor
timestamp: April 06, 2023, 10:31:31 pm
content: I know there are lots of bench DMMs like the 34401A with VFDs. But was there ever a handheld, or at least a battery-powered one ?It's far from impossible: calculators often had VFDs. I know of a handheld VFD thermometer. And there are even battery-operated Nixie meters though they're not so small. But I haven't seen a VFD.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 06, 2023, 10:52:21 pm
content: Calculators with VFD have short battery life. Some only a few hours. I wouldn't want a battery operated DMM with VFD. The Fluke 45 which isn't hand held but it has battery option and has VFD.

author: alm
author_rank: Super Contributor
timestamp: April 06, 2023, 11:44:33 pm
content: VFDs came after LCDs, at least in DMMs. LCDs have been used since the seventies, while VFDs only appeared in the late eighties. And LCD by far superior in terms of battery life. There might have been a bench meter with VFD and a battery option, but I can't recall any. By the time VFDs appeared, bench meter with battery option had mostly been replaced by high end hand helds like the Fluke 8060A/8062A.Before LCD there were (optionally) battery powered meters with LED display like the Fluke 8000A and Keithley 168.

author: tautech
author_rank: Super Contributor
timestamp: April 07, 2023, 02:22:21 am
content: Quote from: alm on April 06, 2023, 11:44:33 pmDates don't seem right.Mom&Pop gave me a Casio calculator ~72 with a VFD which used up 4 AA cells pretty quick however it did have a DC jack and wallwart too.LCD DMM's were quite rare back then IIRC most being moving coils meters, AVO and such.

author: bdunham7
author_rank: Super Contributor
timestamp: April 07, 2023, 03:18:23 am
content: Quote from: tautech on April 07, 2023, 02:22:21 amYes, VFDs appeared earlier than LCD in commercial products, but didn't last very long in battery-operated things like calculators--only a few years IIRC. In watches and calculators and such, those little bubble-digit 7-segment LEDs were next and then LCDs showed up and promptly took over the market. I don't recall ever seeing a DMM with the bubble displays.The whole timespan of what I'm referring to was probably less than 7 years, from ~1971 to 1977. By 1977 LCDs were more common and I think that is when the first handheld DMMs showed up, at least the ones that resemble modern ones.

author: alm
author_rank: Super Contributor
timestamp: April 07, 2023, 08:55:02 am
content: Quote from: tautech on April 07, 2023, 02:22:21 amCan you name a DMM that used VFD in the seventies? I know of nixie tubes (e. g. HP 3450A), LED, LCD but the first DMMs with VFD that I can think of is the Fluke 8840A which appeared in 1985, I believe, and did not come with a battery option. On the HP side I think it was the 3458A which most definitely did not come with a battery option. So I think the Fluke 45, which appeared in 1990, might well be the only DMM with VFD and battery (option) from HP/Fluke/Keithley.Maybe a lesser known manufacturer like Yokogawa or Non Linear Systems was earlier?

author: Oilngas
author_rank: Contributor
timestamp: April 07, 2023, 02:03:18 pm
content: Simpson 460 has a VFD. Mine has IC's dated 7313. Simpson had a later model 460 with the same form-factor that uses LED's. My LED version has IC's dated 7434 and 7438.Both can be powered by 4 internally mounted D cell NiCad's or mains. The VFD version draws around 500 mA, so the batteries don't last long. Both models re-charge when plugged in to the mains.

author: artag
author_rank: Super Contributor
timestamp: April 07, 2023, 03:35:56 pm
content: Quote from: BeBuLamar on April 06, 2023, 10:52:21 pmI had a Commodore calculator with a VFD that seemed to last several weeks. But I wasn't really looking for something that's very good - just for historical interest in gear that was making the best of what was available at the time.I have a Nixie AVO that runs from batteries. I'm not going to be replacing my Flukes with it, but it's a nice curio

author: floobydust
author_rank: Super Contributor
timestamp: April 08, 2023, 08:06:34 pm
content: Simpson 460 that's the only portable multimeter using a fluorescent display I've ever seen. Custom silicon. For its 7-hour rated NiCd life what size are they?In that era, there were many calculators using VFD's with PMOS IC's ok doing direct drive at the higher voltage. But the power drain was high.edit: Simpson 460 review wasFeb. 1972 Popular Electronicsbut Archive.org is being a jerk requiring sign-out to read it. $395 in 1972 is around $2,800 in today's dollars. It weighs 6lbs, 0.1% basic DC.The model seems to have come out in1971multimeter model listing, no idea of the VFD vs LED.Bubble LED's were used in the SinclairPDM351975-ish. It's kinda cute.

author: BeBuLamar
author_rank: Super Contributor
timestamp: April 08, 2023, 08:47:27 pm
content: Quote from: floobydust on April 08, 2023, 08:06:34 pmI think the NiCad in the 460 were 4 sub C cells.

author: factory
author_rank: Super Contributor
timestamp: April 08, 2023, 09:03:15 pm
content: Another one from around 1978, the Hickok 3400, 3410, 3420 DMM, my 3400 has an unpopulated part of the PCB for the battery option.David

author: Oilngas
author_rank: Contributor
timestamp: April 09, 2023, 02:35:24 am
content: The 460 used 4 D cell NiCad. According to the datasheet Eveready CH4 are 4Ah.

author: GigaJoe
author_rank: Frequent Contributor
timestamp: April 09, 2023, 05:11:06 am
content: a popular fluke 45 has option as a battery packi think it around 10-8V , i had some idea to add type-c and battery pack with PDU 12V

author: Gyro
author_rank: Super Contributor
timestamp: April 09, 2023, 10:02:51 am
content: Quote from: factory on April 08, 2023, 09:03:15 pmThat's a nice bright clean display for it's age. There's nothing sadder looking than a fading, uneven VFD on an otherwise good piece of test equipment. It seems to be a more recent phenomenon for some reason. Maybe economising on the number of filaments.

author: floobydust
author_rank: Super Contributor
timestamp: April 09, 2023, 05:55:33 pm
content: Quote from: Gyro on April 09, 2023, 10:02:51 amModern VFD displays are pushed quite hard (to over 50V) and have small (anode) area and greater mux factor with more digits, they need a lot of brightness compared to these older single digit direct-drive tubes. I still have GE Y1938 in an alarm clock I built lol. That tube and the russian ones are very bright even at 15V.Quote from: Oilngas on April 09, 2023, 02:35:24 amI imagine it has a DC-DC converter somewhere for battery operation.The digit driver IC's SCTR0110, 24-pin DIP ceramic and maybe "H" is for Harris, no data. They would be game changers in that era.