Multimeter

Components of a Multimeter

  • Display - four digits and the ability to display a negative sign
  • Selection Knob - allows the user to set the multimeter to read different things such as current, voltage, and resistance
  • Buttons - used to hold (/save) vales
  • Input Jacks - two probes are plugged into two of the ports on the front of the unit

Two Types of Multimeters

These are two types of multimeters. The orange multimeter: 1) shows more accurate values 2) . The black multimeter: 1) automatically scales values, 2) powers off to save battery

Selection Knob

For the orange multimeter, consider the value on the selection knob as the largest possible value.

Voltage

Resistance

Current

Voltage: the difference in charge between two points

  1. Plug the black probe into COM and the red probe into mAVΩ.
  2. Set the multimeter to 2V in the AC/DC range.
  3. Connect the black probe to the battery’s ground or - and the red probe to power or +.
  4. Touch the probes to the positive and negative terminals of the device.
  5. Read the value!

Resistance: a material’s tendency to resist the flow of charge (current)

  1. Pick out a random resistor.
  2. Set the multimeter to the Ω setting.
  3. Hold the probes against the resistor legs.
  4. Read the value!

(The meter will read one of three things, 0.00, 1, or the actual resistor value)

(Do NOT read the resistance of a battery!!!)


Resistor Color Chart

You can identify the resistance of a resistor without a multimeter! Use this chart.

Current: the rate at which charge is flowing

  1. Get an extra piece of wire (VCC).
  2. Pull out the VCC wire going to the resistor.
  3. Add a wire where that wire was connected.
  4. Connect the probe from the power pin on the power supply to the resistor.
  5. Read the value!

(You have to measure current in series)