I apparently have the "original" cheap multimeter that is sold at 2$ now.
It is the Hongda DT-380D (probably chinese) that my dad bought 20-15 years ago, and was around 10-25$ to my guess.
As you can see in the pictures, the outside looks very similar to the one in the video, but the PCB is completely different.
Here's a list the differences between mine and the one Dave tore down in the video:
- It has no SMD components (Except the chip, which looks similar).
- The contacts are going right through the PCB, and that's better than those in the video. (except that the COM contact is too wide so when you connect a probe it can come loose or not make a good connection
).
- There is a 200mA fuse on board, but not a 10A one. There is an additional PTC fuse for something though.
- There is a trimmer for some calibration.
- More passives than the one in the video
- The spring on the top-right side connects ground to a shielding plate in the back cover.
- Square wave output function. I have never actually used it but checked it on an oscilloscope and it outputs some kHz, can't recall what voltage.
Unfortunately this is the meter that I have to use every day
, but fortunately I'm only an hobbyist and it does the job at reading low voltage and resistance and checking for continuity. Can also read mains voltage without blowing up as long as it's in the 600VAC range, I never tried to see if it has input protection in case it is on a wrong range. Anyway I hope to buy a new, better one in the next year.
Just wanted to share this a-little-old piece of hardware, which has at least visually inspired the outside look of these crappy new 2$ multimeters.