Wall Mount DC Power Supply Tester Kit

This very useful kit is a DC Power Supply Tester. It will measure a power supply, such as a Wall Mount Power Supply, and tell you what the voltage is with three different loads. It will also tell you if it is Positive or Negative. The power to drive the Digital Voltmeter is derived from the power source, no external batteries are required.

When measuring a voltage source, it is crucial that the source is measured under a load. If a Wall Mount Power Supply does not specifically state that it is a "Regulated" power supply, then there is a good chance that it is not. What that means is that if you measure the output voltage without a load, the output voltage can be up to twice what its rating is. As you put a varying load on it, you will notice that the output voltage will drop as the load gets heavier. As an example, a 9vdc @ 1 Amp output unregulated power supply can output close to 18 volts dc with no load. This is enough to blow a lot of sensitive devices. As you put a resistor (load) across the output, the voltage will drop to 9vdc, but the load has to be near 1 amp.

Also, if you put a really heavy load, the output voltage will drop well below its rated value. Or blow an internal fuse.

This will Tester will test your power supply with no load, with a light load, a medium load or a high load. The loads are selected by a jumper. If the voltage stays the same throughout the settings, you have a good, regulated DC power supply. The input voltage limit is from 3vdc to 25vdc. This tester will also tell you if the voltage is Positive of Negative by the color of the LED. Simply toggle the switch to get a reading.

There are 3 different ways to connect your DC Power Supply.

The PCB is 2 5/8" x 2 1/2".