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# Electronics

To assess your understanding of this unit use the scale,
'1' = 'I can do very well' to '4' = 'I cannot do at all'. *Credit level emphasised*.

## Overview

- State that an electronic system consists of 3 parts; input process and output.
- Distinguish between digital and analogue outputs.
- Identify analogue and digital signals from waveforms viewed on an oscilloscope.

## Output Devices

- Give examples of output devices and the energy conversion involved.
- Give examples of digital and analogue output devices.
- Draw and identify the symbol for an LED.
- State that an LED will only light if connected one way around.
- Explain the need for a series resistor with an LED.
- State that different numbers can be produced by lighting appropriate segments of a 7-segment display.
*Identify appropriate output devices for a given application.**Describe a circuit diagram which will allow an LED to light.**Calculate the value of a series resistor for an LED.**Calculate the decimal equivalent of a binary number in range 0000 - 1001.*

## Input Devices

- Describe the energy transformations involved in the following devices: microphone, thermocouple and solar cell.
- State that the resistance of a thermistor changes with temperature and the resistance of an LDR decreases with increasing light intensity.
- Carry out calculations using voltage, current and resistance for the thermistor and the LDR.
- State that during charging the voltage across a capacitor increases with time.
- Identify from a list an appropriate input device for a given application.
*Carry out calculations involving voltages and resistances in a voltage divider.**State that the time to charge a capacitor depends on the values if the capacitance and the series resistance.**Identify appropriate input devices for a given application.*

## Digital Processes

- State that a transistor can be used as a switch.
- State that a transistor may be conducting or non-conducting (on or off).
- Draw and identify the circuit symbol for an NPN transistor.
- Identify from a circuit diagram the purpose of a transistor switching circuit.
- Draw and identify the symbols for two input AND and OR gates and a NOT gate.
- State that logic gates may have one or more inputs and that a truth table shows the outputs for all possible input conditions.
- State that: high voltage = logic '1' and low voltage = logic '0'.
- Draw the truth tables for two input AND and OR gates and a NOT gate.
- Explain how to use combinations of digital logic gates for control in simple situations.
- State that a digital circuit can produce a series of clock pulses.
- Give an example of a device containing a counter circuit.
- State that there are circuits which can count digital pulses.
- State that the output of the counter circuit is in binary.
- State that the output of the binary counter can be converted into decimal.
*Explain the operation of a simple transistor switching circuit.**Identify the following gates from truth tables: two-input AND two-input OR NOT (inverter)**Complete a truth table for a simple combinational logic circuit.**Explain how a simple oscillator built from a resistor, capacitor and inverter operates.**Describe how to change the frequency of the clock.*

## Analogue Processes

- Identify from a list, devices in which amplifiers play an important part.
- State the function of the amplifier in devices such as radios, intercoms and music centres.
- State that the output signal of an audio amplifier has the same frequency as, but has a larger amplitude than, the input signal.
- Carry out calculations involving input voltage and voltage gain of an amplifier.
*Describe how to measure the voltage gain of an amplifier.**Carry out calculations involving power, current and resistance (impedance).**Carry out calculations involving input power, output power and power gain of an amplifier.*