Please read this prior article to using your Pokit Pro.
If you are having trouble taking measurements in Voltage, Low Current, Resistance or Capacitance modes with your Pokit Pro, it might be due to a blown 500mA fuse.
The easiest way to check if you have a blown 500mA fuse is to select the middle switch position on the Pokit Pro, set the app to Continuity mode and short (touch) the black probe to the red probe and measure for continuity. If the reading is “OC” and you do not hear a beep from your Pokit Pro, then you likely have a blown fuse. This can be double checked by removing the fuse and checking the continuity across the fuse with another multimeter.
What might be affected by a blown 500mA fuse
The following measurements will likely be affected by a blown 500mA fuse:
- Voltage (AC & DC)
- Low Current (AC & DC)
Note: Sometimes you may still be able to measure some Voltage if the fuse is not 100% open circuit. Additionally, you may be able to measure a small AC Voltage due to capacitive coupling across a blow fuse.
Why the 500mA Fuse may be blown
Due to the size constraints of Pokit Pro, the protection architecture relies on the 500mA fuse for many measurement modes. This makes the Pokit Pro susceptible to blowing the 500mA fuse, thus care must be taken when taking measurements.
When using middle switch position for measurements, care must be taken to not accidentally short the device across a current source that exceeds 300mA.
Care must also be taken when taking the following measurements as a current can flow through the protection and blow the fuse:
- No Measurement mode selected (even if the device is off/disconnected from app)
For this reason, the user should always disconnect the device from any circuit before changing switch position and the user should avoid measuring live circuits in the above modes to avoid blowing the fuse.
Although the Voltage mode uses the 500mA fuse, it cannot blow the fuse due to the high input impedance of the circuit.