MW122A Volt and Ammeter Gauge Holder Frame

thingiverse

This is a holder frame to install a popular “Chinese” volt and ammeter gauge with 100V/10A ratings to a Multi-Voltage Regulated DC Power Supply: MW122A. Installation You will need to drill three (3) holes on the MW122A shell, one hole of 5/16" to pass the volt and ammeter gauge cabling and two 1/16" holes to secure the 3d printed frame. Additionally you will need two (2) 2-28x3/8 Phillips drive screws, or similar. Wiring Notes The following schematic shows the wiring for my particular model, but the wiring for other similar meters is the same. They all can be wired in such a way that you don’t need a separate power supply for the electronics part. You can use the same power supply where your measured load gets electricity. But then you can only measure up to 30V since it’s the maximum operating voltage for the meter itself. Also, keep in mind you can’t accurately measure voltages below 4.5V (if you chose not to use a separate power source for the gauge) as this is the minimum voltage required for the meter. If using the same power supply you even can leave the thin black wire un-connected since they have common ground/GND. Additional Improvements Since the volt and ammeter gauge require a minimum of 4.5V to accurately power the display when the Multi-Voltage Regulated DC Power Supply is sourcing 3V, the display will not work. To solve this issue I got an MT3608 Step Up Boost Converter DC to constantly source 6V to the screen of the volt and ammeter gauge.