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Component 1 Principles of Electronics

5 dot points across 5 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does adding an op-amp to a filter give gain, a sharper roll-off and no loading?

Active filters: op-amp low-pass and high-pass filters, the cut-off frequency, pass-band gain, band-pass filters, and the advantages over passive filters.
An Eduqas A-Level Electronics answer on active filters: op-amp low-pass and high-pass filters with the cut-off frequency and pass-band gain, band-pass filters made by cascading them, and the advantages of active filters over passive ones (gain, buffering and a sharper roll-off).
13 min answer →

How is an audio signal amplified efficiently and faithfully, from microphone to loudspeaker?

Audio systems: the audio chain, voltage and power amplification, gain in decibels, amplifier classes (A, B and AB), crossover distortion, and bandwidth.
An Eduqas A-Level Electronics answer on audio systems: the audio chain from microphone to loudspeaker, voltage and power amplification, gain in decibels, amplifier classes A, B and AB with crossover distortion, and the bandwidth needed for faithful audio reproduction.
13 min answer →

How does an op-amp without feedback compare two voltages, and how does positive feedback give clean, noise-immune switching?

Comparators and Schmitt triggers: the open-loop comparator, the difference between a comparator and an amplifier, positive feedback, hysteresis, and switching thresholds.
An Eduqas A-Level Electronics answer on comparators and Schmitt triggers: the op-amp used open-loop as a comparator, why it differs from an amplifier, how positive feedback creates a Schmitt trigger with two switching thresholds, and how the resulting hysteresis gives clean switching in the presence of noise.
13 min answer →

How do we extract a tiny sensor signal from noise and condition it for the next stage?

Instrumentation systems: sensors and transducers, the Wheatstone bridge, the instrumentation (difference) amplifier, common-mode rejection, and signal conditioning.
An Eduqas A-Level Electronics answer on instrumentation systems: input transducers and sensors, the Wheatstone bridge for small resistance changes, the instrumentation (difference) amplifier with high common-mode rejection, and the signal conditioning that turns a tiny noisy sensor signal into a clean usable voltage.
13 min answer →

How does negative feedback turn a near-perfect amplifier into precise inverting, non-inverting and summing circuits?

Operational amplifiers: the ideal op-amp properties, the inverting, non-inverting, summing and difference amplifiers, the voltage follower, and the virtual earth.
An Eduqas A-Level Electronics answer on operational amplifiers: the ideal op-amp properties, the inverting and non-inverting amplifier gains, the summing and difference amplifiers, the voltage follower as a buffer, and the virtual-earth concept that makes the analysis simple.
14 min answer →