What is voltage gain and how is it calculated?

Voltage gain is how many times bigger the output is than the input, G equals V out divided by V in. It is a ratio, so it has no units. Both voltages must be in the same unit before dividing. You can rearrange it to find the output, V out equals G times V in.

What are bandwidth and clipping?

Bandwidth is the range of frequencies over which an amplifier gives useful, fairly constant gain; the gain falls off at high frequencies, and higher gain usually means narrower bandwidth. Clipping is distortion where the peaks of the output are flattened because the output cannot exceed the supply voltage.

What is the gain of an inverting and a non-inverting amplifier?

The inverting amplifier has gain equal to minus the feedback resistor over the input resistor, and the minus sign means the output is inverted. The non-inverting amplifier has gain equal to one plus the feedback resistor over the input resistor, and keeps the output the same way up, always with a gain greater than one.

What is a summing amplifier (mixer)?

A summing amplifier is an inverting amplifier with several inputs, each through its own resistor, all feeding the inverting input. The output is proportional to the sum of the inputs, so it combines several signals into one. This is the basis of an audio mixer, which blends several sound sources.

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WJEC GCSE Electronics: operational amplifiers overview

Q: How are operational amplifiers examined?

It sits in Component 2 (Application of Electronics), a 1 hour 30 minute written paper worth 40% of the GCSE. Expect voltage gain calculations, gain-frequency and bandwidth reasoning, clipping explanations, inverting and non-inverting gain calculations, mixer descriptions, and drawing an amplifier system block diagram.

An overview of the operational amplifiers content in Component 2 of WJEC Eduqas GCSE Electronics, covering amplification and voltage gain, the gain-frequency response and bandwidth, clipping, the inverting and non-inverting amplifier gain equations, the summing amplifier (mixer), and the amplifier system block diagram.

Generated by Claude Opus 4.86 min readWJEC Eduqas GCSE Electronics, Component 2Updated 2026-06-15

Reviewed by: AI editorial process; not yet individually human-reviewed

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For the official specification

The operational amplifiers content of WJEC Eduqas GCSE Electronics opens Component 2 (Application of Electronics). It covers what amplifiers do, voltage gain, bandwidth and clipping, the inverting and non-inverting op-amp circuits, the summing amplifier (mixer), and the amplifier system. This page maps the content and links to a focused answer page for each part.

What the topic covers

Amplifier basics and gain. Amplification as increasing voltage and power, the voltage gain equation $G = \dfrac{V_{\text{out}}}{V_{\text{in}}}$ , the gain-frequency response and bandwidth, and clipping distortion. See Amplifier basics and gain.

Op-amp circuits and mixers. The inverting amplifier ( $G = -\dfrac{R_f}{R_{\text{in}}}$ ) and the non-inverting amplifier ( $G = 1 + \dfrac{R_f}{R_{\text{in}}}$ ), the summing amplifier (mixer), and the amplifier system block diagram from source to loudspeaker. See Op-amp circuits and mixers.

How this content is examined

This content sits in Component 2 (Application of Electronics), a written paper of 1 hour 30 minutes worth 40% of the GCSE. Expect voltage gain calculations, gain-frequency and bandwidth reasoning, clipping explanations, inverting and non-inverting gain calculations, mixer descriptions, and drawing an amplifier system block diagram.

How to study it

Gain is a ratio. $G = \dfrac{V_{\text{out}}}{V_{\text{in}}}$ , no units, same units top and bottom.
Know the two gain equations. Inverting $-\dfrac{R_f}{R_{\text{in}}}$ ; non-inverting $1 + \dfrac{R_f}{R_{\text{in}}}$ .
Explain clipping clearly. Peaks flatten at the supply when the gain or input is too large.
Understand the mixer. A summing amplifier adds several inputs into one output.
Draw the system. Source then pre-amplifier then mixer/gain then power amplifier then loudspeaker.

For the official specification

WJEC Eduqas publishes the full GCSE Electronics specification, past papers and mark schemes at wjec.co.uk. Always revise from the current specification and the board's own past papers, because question style and the printed equation and symbol lists are board-specific.

Sources & how we know this

WJEC Eduqas GCSE Electronics specification (from 2017) — WJEC Eduqas (2017)