The Multimeter is the most useful tool in diagnosing electronic circuits. If you are keen to progress further in electronics a multimeter is a must have in your tool box. It can be used to measure a range of electronic principles but most commonly used for the measurement of Voltage (in Volts), Current (in Amps) and Resistance in (Ohms).
- Turn multimeter dial to the Ohms symbol, ensure leads are plugged into Com and V sockets as shown in picture bellow (Measuring Resistance).
- Touch leads across two legs of a resistor while it is not in a circuit. You should get a reading that is close to the expected value of the resistor. for example if you chose a 330 ohm resistor (orange, orange, brown, gold) you should get a value between 214 and 346 Ohms. (this difference is due the to tolerance of the resistor and we are using 5% tolerance).
- Complete the circuit under measuring voltage.
- Turn the multimeter dial to V (DC) and attach an alligator clip to each lead of the multimeter.
- Clip the two alligator clips to either side of the LED as shown in the circuit bellow.
- Connect the power supply and read the voltage across the LED
- Try replacing the Resistor with a 1K resistor and take note of the brightness of the LED and voltage value on the Multimeter
- Disconnect the alligator clips from the LED and put the Multimeter into A (Amps) mode to measure the current by turning the dial
- To measure the current flowing through a circuit you need to break the circuit and inset the multimeter
- Connect the alligator clips between the LED and the Resistor
- Observe the current measurement in mA (Milliamps)
- Swap the resistor with a 1K or 10K resistor and observe the change of current on the multimeter and brightness of LED
- Record findings in Learning Journal
Fritzing Breadboard Layout and Schematic Diagram: