An electrical signal is a changing electrical quantity, usually voltage or current, in a wire, cable, or electronic circuit.
Examples include:
- signals traveling through copper Ethernet cables,
- audio signals inside electronic circuits,
- voltage pulses inside digital electronics.
A simple way to think about it is:
Electrical signal = changing voltage and/or current
For example:
Voltage
↑
| /‾\ /‾\
| / \ / \
|____/ \__/ \____ → TimeThe graph shows how the voltage changes over time.
An electromagnetic signal is a changing combination of electric and magnetic fields that propagates through space or through a medium.
Examples include:
- Wi-Fi signals,
- cellular signals,
- radio broadcasts,
- satellite communication,
- microwave communication.
A simple way to think about it is:
Electromagnetic signal = changing electric and magnetic fields traveling as a wave
For Wi-Fi, the process is approximately:
Digital data
↓
Electrical signal inside the device
↓
Antenna
↓
Electromagnetic radio signal
↓
AirThe antenna converts the high-frequency electrical signal in the circuit into an electromagnetic wave that travels through the air.
Main Difference
| Electrical Signal | Electromagnetic Signal |
|---|---|
| Usually described in terms of voltage and current | Described in terms of electric and magnetic fields |
| Commonly travels through conductors or circuits | Can travel through air or space |
| Example: copper Ethernet cable | Example: Wi-Fi |
| Often measured as voltage versus time | Often discussed as radio waves, frequency, field strength, or wavelength |
The two ideas are related.
A changing electrical current can create changing electric and magnetic fields. This is how an antenna produces a radio signal.
Similarly, when an electromagnetic radio wave reaches a receiving antenna, it causes a small electrical signal in the antenna and receiver circuitry.
So the relationship can be shown as:
Electrical signal
↓
Antenna
↓
Electromagnetic signal
↓
Antenna
↓
Electrical signalFor networking, a simple distinction is:
- Copper cable → electrical signal
- Fibre-optic cable → optical/light signal
- Wi-Fi → electromagnetic/radio signal
One subtle point is that electrical signals in real cables also involve electromagnetic fields physically. However, in normal engineering and networking terminology, a signal carried through a copper conductor is usually called an electrical signal, while a wireless signal traveling through the air is usually called an electromagnetic or radio signal.
From AI Tools as is.
