What is worse than a battery powered multimeter?
A battery powered multimeter with an empty battery.
That’s why I have to upgrade this multimeter with a power socket, a step-down converter to support a wide input voltage range, and an isolated DC-DC converter to isolate the input voltage from the multimeter circuits.
Outside view of the multimeter, same as before, except with a power socket:
The power supply circuit fits nicely into the battery compartment. The green PCB is a MC34063 based stepdown converter. To the right of it is the isolated DC-DC converter.
The power supply PCB is pluggable. I can take it out, put a battery inside and walk through the house with the multimeter.
I wonder why new multimeters don’t have anything like this. It wouldn’t be hard to add USB socket to power the multimeter, charge batteries and also control the meter from a computer. Even these much overpriced banana-meters have not one of these features.