The Micronta line of electronic multimeters, sold for decades through Radio Shack stores, offered a wide range of entry and intermediate-level models. The model 22-167 was a typical example of an intermediate-level Micronta digital multimeter, providing measurement of current, voltage and resistance with 3 3/4 digits of precision.
Analog and Digital
The many models of Micronta multimeters generally fall under two main types: analog and digital. An analog multimeter uses a mechanical needle movement on a dial to display voltage, current and resistance measurements; digital models use a modern liquid crystal display; some offer additional measurement modes such as continuity, diode check and capacitance. Most digital models automatically find the correct measurement range and polarity.
Things You'll Need:
- 9-volt battery
- 1K-ohm resistor
Setup and Power-On
- Press the power button on the meter.
- Insert the red meter probe into the jack marked VΩ. Insert the black probe into the COM jack.
The meter has an automatic battery check function. The meter displays -[+ / -] when the battery is marginal. Replace the meter’s internal battery if the display does not turn on or you see the -[+ / -] symbol.
Turn the meter’s selector knob so it points to the --V function, used for measuring the voltage of direct current.
Touch the metal tip of the red probe to the battery’s positive terminal. Touch the tip of the black probe to the negative terminal.
Read the meter display. You should see a measurement of about 9 volts; the exact figure depends on the condition of the battery.
Press the Data-H button to hold the data in the meter. Disconnect the probes from the battery. Observe that the display retains the voltage reading even though the probes no longer touch the battery. Press the Data-H button again and observe that the display returns to reading of zero volts.
Disconnect the probes from the battery.
Turn the function selector switch so it points to the Ω function, indicating resistance measurement in ohms.
Touch one probe tip to one lead of the resistor. Touch the other probe tip to the resistor’s unconnected lead.
Read the meter display. You should see a measurement of about 1,000 ohms, depending on the resistor’s actual value. For example, you may see a reading of 900 ohms for a 1K resistor whose tolerance is 10 percent.
Disconnect the probes from the resistor.
Turn the function selector so it points to the 32/320 mA setting. This setting measures DC current in the milliamp range.
Connect one of the resistor leads to the positive terminal on the battery.
Touch the metal tip of the red probe to the resistor’s free lead. Touch the tip of the black probe to the battery’s negative terminal.
Read the meter display. You should see a measurement of about 9 milliamps, depending on the actual battery voltage and resistor value.
Disconnect the probes from the resistor and battery. Disconnect the resistor from the battery.
- Do not measure DC currents for voltages greater than 750V with this meter.
Chicago native John Papiewski has a physics degree and has been writing since 1991. He has contributed to "Foresight Update," a nanotechnology newsletter from the Foresight Institute. He also contributed to the book, "Nanotechnology: Molecular Speculations on Global Abundance."