diode will conduct electrons only in one direction
A small forward potential difference is needed to
turn the diode on.
a diode can bec used to produce direct current
from the alternating current leaving a transformer (rectification).
Recognise the AC and rectified (pulsed DC)
a capacitor can be used to store a charge during the
non-conducting part of the cycle to provide a smoothing effect, and hence
Be able to recognise the waveform of smoothing
a light emitting diode (LED) is made from a material
that will produce light when passing a suitable direct current.
a variable capacitance diode behaves like a capacitor
and that the capacitance can be varied by changing the applied potential
a transistor (npn) can be used as an amplifier.
a small base current on the transistor will control
a larger collector current and that this is the basis of amplification.
if the base current is large enough, the transistor
behaves as a switch such that the current in the collector can be turned
on and off.
a transistor can be used as an oscillator to generate
audio and radio frequencies.
distinguish between a crystal oscillator and a variable
frequency oscillator (VFO) based on a tuned circuit.