Transistors

• Unfortunately I don't have a great on line reference for transistors
  • (YET)
  • Wikipedia will do for now.
• Transistors are electronic switches.
  • They were first realized in 1957 at bell labs.
  • They are currently mostly made from silicon.
  • But we continue to look for something faster.
  • Graphene, Gallium Nitride, Silicone Carbide,
  • I can't find a good article that is not behind a paywall.
• Transistors replaced vacuum tubes in the early computer days.
• Eventually transistors were incorporated into an integrated circuit
  • Again wikipedia is good.
  • Look at the Generations of ICs.
• There are several different structures of transistors
  • metal-oxide-semiconductor field-effect transistor (MOSFET)
  • Bipolary Junction Transistor (BJT)
  • ...
  • We really don't care about this.
• There are two different Electrical Polarity types we care about.
  • NPN and PNP
  • N-Channel, P-Channel
  • Digital uses N-Channel and P-Channel
  • I think the ones I have are NPN and PNP
  • For our purposes it doesn't matter.
• In N-Channel, P-Channel
  • There is a Source labeled S
  • There is a Drain labeled D
  • There is a Gate labeled G
  • (Wikipedia)
  • 
• In NP and PNP
  • There is a Emitter labeled E
  • There is a Collector labeled C
  • There is a Base labeled B
  • (Wikipedia)
• For us
  • The source or emitter is the source of either 1 or 0
  • The drain or collector is the output of the circuit
  • The gate or base is the part that controls the circuit.
• PNP or P-Channel
  • Hook a positive to the source or emitter.
  • Hook an output to the drain or collector.
  • Hook a switch (or input) to the base or Gate.
  • When the Gate has a 0, the drain or collector will have a 1
  • 
  • When the gate has a 1, the drain or collector will have nothing.
  • 
• NPN or N-Channel
  • Hook a negative to the source or emitter.
  • Hook an output to the drain or collector.
  • Hook a switch (or input) to the base or Gate.
  • When the Gate has a 0, the drain or collector will have a 1
  • 
  • When the gate has a 1, the drain or collector will have nothing.
  • 
• Some circuits
• The physical example of PNP and NPN
  
  • The digital file
  • I am using a BC327 PNP
  • I am using a BC337 NPN