Thermal, shot and flicker noise limit the smallest detectable signals.
Thermal noise v_n=√(4kTRB), shot noise and flicker (1/f) limit the smallest signals. Noise figure and signal-to-noise ratio quantify performance. Reduce by lowering bandwidth, choosing low-noise parts, cooling and good shielding.
A 10 kΩ resistor at 20 kHz bandwidth produces about 1.8 µV RMS noise.
Noise sets the smallest signal a circuit can resolve, so it limits sensors, radios and precision instruments.
Thermal, shot and flicker noise limit the smallest detectable signals.
Noise sets the smallest signal a circuit can resolve, so it limits sensors, radios and precision instruments.
Random electron motion in a resistor due to temperature, which produces a noise voltage proportional to the square root of resistance, temperature and bandwidth.
Noise that increases at low frequencies, often caused by imperfections in semiconductor interfaces, and it can dominate in DC amplifiers.
Typical applications include choosing a low-noise op-amp for a strain gauge bridge, estimating the noise floor of a radio receiver and reducing flicker noise in a precision amplifier by choosing a larger device.
Study "Voltage regulators" first (topic 29 of 104 in Electronics & Embedded). It covers the groundwork this topic builds on.
Johnson-Nyquist noise. Input-referred noise. Averaging improves SNR by √N.
A 10 kΩ resistor at 20 kHz bandwidth produces about 1.8 µV RMS noise.
The next topic is "Grounding and PCB layout", which builds directly on this one.
It is classed as Beginner in Electronics & Embedded (topic 30 of 104). It is an entry-level topic. It relies only on basic school mathematics and the ideas introduced earlier in this discipline.
Want to practise? Open the interactive course for quick checks, quizzes, simulations and progress tracking.