Iain's Electronics Page
Using a Multimeter
Measuring Voltage
To measure voltage on a battery.This is an example of a 1.4 AA battery.
- black goes to the negative and red to the positive or knobbley end.
- make sure black lead is in COM on the multimeter
- make sure red lead is in V on the multimeter
- connecting in correctly will result in a negative number
- the numbers in the V section are the range in mA.
- using the 200mA will result in 1364 or 1.364 Volts
Measuring Voltage of a Circuit
Below we have a circuit with a battery, resister and LED.
Here would be the circuit diagram.
In circuit is said to be in series as one component follows another. We can measure the voltage across any one of the components individually. To measure you connect the multiimeter in parallel which means you put the probes either side of the component. This is said to be measuring in parallel. As usual the black goes to black (negative).
Example of measuring the voltage of the LED.
In our case they measured
- 2.83 battery
- 2.3 led
- 0.64 Resister
Which means the voltage of the led and resister = voltage of the battery.
Measuring Current of a Circuit
This will be the same where ever we measure for the circuit.
Key Points to measure Current
- Always set the meter back to volts when done because you might blow the fuse
- Always' use the top socket on the multimeter to start because you might blow the fuse
- To measure the current we need to add the probes in series
See the probes are added to the circuit.
Measuring Resistance
Set to Ω Ohms to measure resistance. Always measure unplugged and not in a live environment. Same as before. Set multimeter to Ohms and use the range appropriately.
Checking a Conductive Path
The final setting which looks like a diode beeps if there is a conductive path. We can now test the circuit to ensure that components are connected.
Breadboards
Origin
This comes from when they did use bread boards with screws in to make a circuit
Usage
Basically they operate horizontally in the middle and vertically on the outside. Typically the outside rails are for the power supply.
Example Circuit
We can see the + and - of the batter is flowing vertically and the components are connected horizontally.
Passive Components
A passive component is an electronic component which can only receive energy, which it can either dissipate, absorb or store it in an electric field or a magnetic field. Passive elements do not need any form of electrical power to operate.
Common examples of passive components include:
- Resistors
- Inductors
- Capacitors
- Transformers
Resisters
Purpose
A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element. In electronic circuits, resistors are used to reduce current flow, adjust signal levels, to divide voltages, bias active elements, and terminate transmission lines, among other uses.
Reading Resisters
Here is a chart for reading resisters.
Inductors
Purpose
An inductor, also called a coil, choke, or reactor, is a passive two-terminal electrical component that stores energy in a magnetic field when electric current flows through it. An inductor typically consists of an insulated wire wound into a coil around a core. Inductors are typically used as energy storage devices in switched-mode power devices to produce DC current. The inductor, which stores energy, supplies energy to the circuit to maintain current flow during “off” switching periods, thus enabling topographies where output voltage exceeds input voltage
Types
The commonly seen inductor, with a simple winding is this air-Core Inductor. This has nothing but air as the core material. The non-magnetic materials like plastic and ceramic are also used as core materials and they also come under this air-core Inductors.
Capacitors
Purpose
The capacitor store current which can be released when the circuit is under load and the current drops.
Types
There are different types of capacitor. Electrolytic capacitors and Ceramic capacitors are two common types. The Electrolytic capacitors have a positive and negative (or polarized) and will explode when failing this is because the component contains a liquid inside which can boil.
Equivalent series resistance
Must read up on this.