This is neat, and surprisingly cheap too. Instead of just being a panel indicator light it also displays the supply voltage. That's a very nice solution for quick diagnostics. The quality of construction seems OK. Very simple and well rated components for standard mains voltages, although the sense resistor may not be rated for the higher phase to phase voltages.
Power dissipation is low at about half a watt with predictably poor power factor (0.07) because of the simple capacitive dropper and low circuit voltage. There's no significant heat being dissipated on the PCB.
The music track referenced is an old fairground classic called Dominator:-
https://www.youtube.com/watch?v=-dohzrXT09w
Carl Cox mix:-
https://www.youtube.com/watch?v=iYvrXtmrLSY
Here's a universal ebay search link for the meters:-
https://www.ebay.com/sch/i.html?_from=R40&_sacat=0&LH_BIN=1&_nkw=22mm+voltmeter&_sop=15
If you enjoy these videos you can help support the channel with a dollar for coffee, cookies and random gadgets for disassembly at:-
http://www.bigclive.com/coffee.htm
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14 thoughts on “Inside a 22mm digital panel indicator/voltmeter.”
  1. Avataaar/Circle Created with python_avatars зроблено руками says:

    Some noname-dedicated ic. Its a so-14 package, the 1st and 14th leg ment for power supply (+5v) and a common ground. And the 9th leg appear to be adc input with internal reference of 1.1 volts. Easyly can be converted to dc ampere meter.

  2. Avataaar/Circle Created with python_avatars Father Loz says:

    Bought the AC version instead of DC lol, could they still be used to test DC ? 🙂 thx !

  3. Avataaar/Circle Created with python_avatars PCB LAND says:

    Amazing my friend ♥♥♥♥♥

    Nice to meet you ♥♥♥♥♥

    Best wishes for you ♥♥♥♥♥

    Keep it up ………. ♥♥♥♥♥

  4. Avataaar/Circle Created with python_avatars Engineer says:

    I was seeking for this video. My 4 digital LED indicator stopped working. Dont know what gone wrong.

  5. Avataaar/Circle Created with python_avatars West Bay says:

    If I have this in circuit always on, will it draw power and reduce my DC output. If so, by how much. I need to maintain a certain voltage.

  6. Avataaar/Circle Created with python_avatars Robert Huntley says:

    I've got a version of those that plugs into a car cigarette lighter socket, which costed a whole £3 including postage from China. I use it to keep a rough check on my car battery state of charge (my car has a smart charging system, and swaps from circa. 14.4 volt when actually charging the battery, to 12.3V when its fully charged and being floated).
    Only using the car once a week due to Covid lockdown etc., and was surprised to see that it takes well over half an hour to charge the battery after the long shut down period.

  7. Avataaar/Circle Created with python_avatars Joey White-Swift says:

    @bigclivedotcom I didn't see it asked in the other comments, but did you test the current draw of the meters? It would be nice to have a rough idea how much they would cost to operate…

  8. Avataaar/Circle Created with python_avatars Olivia BallsDeet says:

    Weird question, could I use one of these to monitor the current going to a large dc motor? Connecting it between the input and output?

  9. Avataaar/Circle Created with python_avatars Jim Wilson says:

    was looking for a mini VDC gauge ……. so using your info found the DC versions thanks mate

  10. Avataaar/Circle Created with python_avatars Gadget :p says:

    Bought one of these a while back, due to the numerous power failures we experience (and an even more important reason! (Long story, won't go into it here)), and connected it to the incoming feed of the earth leakage.

    It works like a charm, as I can now just glance over at the DB Board and see if they have granted us the Privelage of municipal power that we pay for every month, but hardly get.

  11. Avataaar/Circle Created with python_avatars Foo McBar says:

    That Carl Cox remix is bangin'

  12. Avataaar/Circle Created with python_avatars db says:

    Any mod to measure voltages starting from 0V?

  13. Avataaar/Circle Created with python_avatars Gran Patriarca says:

    That ebay seller is very famous i buy it them some electronics several years ago.

  14. Avataaar/Circle Created with python_avatars Rajkumar Kushwaha says:

    भईया मेरे घर में दस पंखा दो मोटर बल्ब करीब पच्चीस पीस 7 वाट का और दो टीवी होम थियेटर और कूलर फ्रिज वाशिंग मशीन इतना मेरे घर लाइट का खर्चा है तो मै कितना एम्पियर का चेंजर लगाऊ प्लीज भईया जल्द बताइए

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