Physics 7408/3BE June 2019

The AQA Paper 3 Physics exam (June 2019), Section B (Electronics), explores various topics related to digital circuits, operational amplifiers, sensors, and communication systems. Key subjects include Johnson decade counters, the design of traffic light sequences using logic gates, and the calculation of suitable resistors for LED circuits. The exam also covers operational amplifier configurations, including audio mixing desk circuits, and the use of Hall effect sensors for monitoring fluid levels and rotational speeds. Additional topics involve Zener diodes, logic gates, and pulse code modulation (PCM) with time division multiplexing (TDM), along with the working principles of regenerators in communication systems.