Page 29 - CITS - Electronic Mechanic - TT - 2024
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ELECTRONICS MECHANIC - CITS
2 Implementing AND gate
The AND gate is replaced by a NOR gate with all its inputs complemented by NOR gate inverters
3 Implementing OR gate
The OR is replaced by a NOR gate with its output complemented by a NOR gate inverter.
Constructing Gates by using Transistor
A transistor is adevice that acts, depending on the voltage level of an input signal, either asa wire that conducts
electricity or as a resistor that blocks the flow of electricity
A transistor has no moving parts, yet acts like a switch.
It is made of a semi conductor material, which is neither a particularly good conductor of electricity, such as copper,
nor a particularly good insulator, such as rubber.
A transistor is shown below :
Transistor
A transistor has three terminals
1 A source
2 A base and
3 An emitter – typically connected to a ground wire
If the electrical signal is grounded, it is allowed to flow through an alternative route to the ground (literally) where
it can do no harm.
It turns out that, because the way a transistor works, the easiest gates to create are the NOT, NAND and NOR
gates shown below :
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CITS : E & H - Electronics Mechanic - Lesson 5 - 8
