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Component 1 Discovering 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 a diode pass current one way only, and what is it used for?

Diodes: forward and reverse bias, the forward voltage drop, the LED, rectification, and protecting circuits against reverse current and back-EMF.
An Eduqas GCSE Electronics answer on diodes: forward and reverse bias, the forward voltage drop, the light-emitting diode, half-wave rectification of a.c. to d.c., and using a diode to protect a circuit from reverse polarity and from the back-EMF of a relay or motor.
13 min answer →

How can a switching circuit latch on and stay on, and how does feedback give a clean switching action?

Latching switches and feedback: using a relay or positive feedback to latch an output on, the need for a reset, and how feedback gives a snap (Schmitt) action that avoids chatter.
An Eduqas GCSE Electronics answer on latching and feedback in switching circuits: using a relay or positive feedback to hold an output on once triggered, the need for a reset, and how positive feedback produces a clean snap (Schmitt) switching action that avoids chatter near the threshold.
12 min answer →

How is a MOSFET used as a voltage-controlled switch, and how does it compare with a bipolar transistor?

MOSFET switching: the MOSFET as a voltage-controlled switch, the gate threshold voltage, why it draws no steady gate current, and choosing between a MOSFET and a bipolar transistor.
An Eduqas GCSE Electronics answer on the MOSFET as a switch: voltage control by the gate, the gate threshold voltage, why a MOSFET draws essentially no steady gate current, switching higher-current loads, and choosing between a MOSFET and a bipolar transistor for an output stage.
12 min answer →

How is a bipolar transistor used as a switch to turn a load on from a small input current?

Transistor switching: the bipolar transistor as a switch, cut-off and saturation, current gain, and choosing the base resistor to drive a load.
An Eduqas GCSE Electronics answer on using a bipolar transistor as a switch: the cut-off and saturation states, current gain relating collector and base current, and choosing the base resistor so a small input current turns on a larger load current.
13 min answer →

How does a comparator switch its output when a sensor voltage crosses a reference level?

Comparators: comparing two voltages, the reference set by a potential divider, the digital output, and using a comparator to make a sensing system switch at a threshold.
An Eduqas GCSE Electronics answer on comparators: how a comparator compares two input voltages and switches its output high or low, setting the reference with a potential divider, the digital nature of the output, and combining a sensor divider with a comparator to switch a circuit at a chosen threshold.
13 min answer →