- William B. Shockley (1910-1989)
- Known as the Father of the Transistor
- joined Bell Labs in 1936 in the vacuum tube department (solid state physicist)
- Moved to the semiconductor laboratory: –It has today occurred to me that an amplifier using semiconductors rather than vacuum tubes is in principle possible. Invented in 1944.
Two different symbols are used for the transistor.
- Functions in Analog
- The transistor’s function is to amplify an electric current.
- Many different kinds of transistors are used in analog circuits, for different reasons. This is not the case for digital circuits.
- Functions in Digital
- In a digital circuit, only two values matter; on or off.
- The amplification ability of a transistor is not relevant in a digital circuit.
- In many cases, a circuit is built with integrated circuits(ICs).
- Transistors are often used in digital circuits as buffers to protect ICs.
- For example, when powering an electromagnetic switch (called a ‘relay’), or when controlling a light emitting diode. (In my case.)
Water Analogy of transistors
Understanding Example One.
Understanding of Example Two
Understanding of Example Three
Understanding of Example Four
FIND OUT THE TRANSISTER CODING
|A=germanium||A=diode||Special or general purpose|
|B=silicon||B=variable capacitance diode|
|C=gallium arsenide||C=A. low power transistor (low power low frequency)|
|D=compound material (Ex Cadium sulphide)||D=A.F low power transistor (high pass low frequency)|
|F=H.F low power transistor (low pass high frequency|
|H=magnetic sensitivity diode|
|L=H.F power transistor (high pass high frequency)|
|P=radiation resistive diode|
|Q=radiation generating diode|
|R=thyristor (SCR or triac)|
|S=Low power switching transistor|
|U=Power switching transistor|
|Z= Zener diode|
- BC547 – general purpose low pass low frequency silicon transistor
- ADF – special purpose high pass low frequency germanium transistor
- SL100 – general purpose high pass high frequency silicon transistor
- 2SAXXXX PNP type high frequency
- 2SBXXXX PNP type low frequency
- 2SCXXXX NPN type high frequency
- 2SDXXXX NPN type low frequency