PracticalTheExpandedToolbox/Lab1
Contents
Lab1: Measuring volts, current and resistance
Introduction
Taking measurements on a circuit is an essential skill when working with electronics. Even for the simplest problems usually the first checks will be similar to the following:
- is there enough voltage for the circuit to work (dead battery?)
- is there current flowing (loose connection?)
- is the current flowing what you would expect or perhaps more (short circuit?) or much less (loose connection?)
Taking measurements will also give you invaluable and often necessary insights in the working of a circuit. So, for example, to know how long your project will be running on a battery it is necessary to know how much current the circuit uses.
Note: If you are unfamiliar or have forgotten about metric prefixes like mega, kilo, milli, micro etc. please refresh this here: Metric Prefixes and SI Units
Description
In this lab you will use a Digital MultiMeter (DMM) to take measurements in a simple circuit.
* First read the required reading material indicated in the schedule for the Intro into Electronics: PracticalTheExpandedToolbox#Schedule * Read the SparkFun tutorial on using the a Digital Multi Meter
Measuring Voltage
What you need (ask at the Interaction Station):
* Multimeter * 9 Volt battery (5V in the tutorial) * 9 Volt battery clip for in a breadboard * 470 Ohm resistor (1K Ohm in the tutorial) * LED
Carry out the SparkFun tutorial section about measuring voltage: https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter#measuring-voltage . Keep track of you measurements and note these down on your WiKi. If you don't know how to use the WiKi yet not them down elsewhere so you can not them on the WiKi after the WiKi introduction.
Note: instead of the 5V breakout board the tutorial uses you are using a 9V battery.
This means your measured values will differ from the results in the tutorial. Your resistor value and LED forward voltage will differ as well.
Important: be careful with your units!! Saying there is a voltage drop of 1 volt (V) across a resistor while you are measuring a millivolt (mV) means you are a 1000 times (3 orders of magnitude) off.
Measuring resistance
What you need (ask at the Interaction Station):
* Multimeter * 3 random resistors * 3 resistors of the same value
Resistors come in a wide variety of values, tolerances, wattage and packages. The most common (hobby)resistor is the 1/4 Watt resistor with a tolerance of 5% (meaning the real value of the resistor can be 5% lower or higher than the indicated value). These resistors are usually beige in colour. At the Interaction Station you will probably get resistors that are light blue. These are still 1/4 Watt resistors but have a tolerance of 1%.
First Again carry out the SparkFun tutorial section about measuring resistance: https://learn.sparkfun.com/tutorials/how-to-use-a-multimeter#measuring-resistance .
