1. A very gentle intro

2. The invention that changed everything… The real thingCircuit diagram symbol

3. What transistors are good for ~731M transistors in Intel core i7

4. Transistor action: BJT BJT = Bipolar Junction Transistor Goal: control current flow from collector to emitter via base Fluid Analogy: Small signal controls a much larger signal

5. Transistor action: electron flow N N P Emitter Base Collector - - - - - - For conventional current flow (tracking positive charge movement), flip the arrows!

6. Bipolar Transistor Parameters BE: fwd biasBC: rev bias

7. Input characteristic Transistor ON  Fwd biased diode Working on the steep part of the curve (blue dotted box highlights normal operating range)   V BE small   I B relatively large * Rule of thumb: use V BE ~ 0.7V when designing BJT circuits IBIB V BE IBIB

8. Output Characteristic Active region (light blue): I c =  I B I c ~independent of V CE Saturation (yellow-ish): I c depends on V CE and I B 0.3V

9. Load Line 1. KVL in loop through transistor give us the load line 2. One point for saturation: V CE = 0, I c is maxed 3. One point for cutoff : I c = 0, V CE is maxed 4. Operating point: intersection of load line and characteristic curve

10. Load Line Example V CC = 10 V R L = 400  V LED = 1.6 V (red) Assume I B  1. 0 = V CC – V LED – I C R L – V CE 2. V CE = 0  I C = (V CC – V LED )/R L = 21.0 mA 3. I C = 0  V CE = V CC - V LED = 8.4 V

11. Load Line for example circuit  Actual current will be about 18 mA, a little less than designed for, but not bad!

12. Image credits  http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/comp/active/BiPolar/bpcur.html http://www.st-andrews.ac.uk/~www_pa/Scots_Guide/info/comp/active/BiPolar/bpcur.html  http://www.electronics-tutorials.ws/transistor/tran_2.html