Transistor Circuit Templates This presentation is partially animated. Only use the control panel at the bottom of screen to review what you have seen. When using your mouse, make sure you click only when it is within the light blue frame that surrounds each slide.

NPN transistor circuit template current meter 0 current meter 0 volt meter volt meter n n p pn junctions This transistor is in conduction collector base emitter current meter volt meter n p pn junction This diode is forward biased anode cathode 1 pn junction 2 pn junctions

volt meter n n p pn junctions resistance varies as resistor knob is turned. emitter If the input signal and the output signal are “grounded” at the same potential the circuit is know as a common-emitter circuit. output signal This transistor is connected in a common-emitter circuit d vWhen gets high enough, the light will turn on. input signal d If v gets higher, the light will become brighter. NPN transistor circuit template v d goes up as the variable resistance value goes up. Voltage here,, knob is turned so light goes on. knob is turned more so light gets brighter.

volt meter 0 n n p E This transistor is connected in a common-emitter circuit Variable Resistor R 1 R v 1 = R v R 1 + R v R 1 v d goes up as the variable resistance value goes up. Voltage here,, v t v t [] v d = v t - v 1 d vWhen gets high enough, the light will turn on. output signal input signal Many sensors are designed to provide a variable resistance output signal. NPN transistor circuit template

volt meter 0 n n p E This transistor is connected in a common-emitter circuit R v t = time the voltage across these two terminals v in At low voltage value, light is OFF. high value Low value At high voltage value, light is ON. output signal input signal v in Example of a digital circuit - a buffer NPN transistor circuit template

volt meter 0 n n p E This transistor is connected in a common-emitter circuit R v t time At low voltage value, light is ON. high value Low value At high voltage value, light is OFF. Example of a digital circuit - an inverter v in NPN transistor circuit template the voltage is applied across these two terminals v in

volt meter 0 n n p E This transistor is connected in a common-emitter circuit R v t time high value Low value high voltage value Example of a digital circuit - Flip-flop Output v in low voltage value NPN transistor circuit template v in the voltage is applied across these two terminals

volt meter 0 n n p E This transistor is connected in a common-emitter circuit R v t time high value Low value high voltage value Example of a digital circuit - Flip-flop Output v in low voltage value NPN transistor circuit template v in the voltage is applied across these two terminals

volt meter 0 n n p E This transistor is connected in a common-emitter circuit R v t Example of a linear output circuit v in NPN transistor circuit template R 3 R 2 There is a voltage at the orange node because of the voltage divider circuit element highlighted in blue. Voltage divider output set so transistor is just barely conducting. This light get brighter as input signal is linearly increased. This light get dimmer as input signal is linearly increased. This input signal is varied linearly to brighten/dim the lights. R 3 v t [] R 3 R 2 + v d = v t - v d

n 0 current meter R sensor Template for monitor circuit V + Reference voltage often not used. v be p E n V ref R pull up Output circuit to monitor resistive sensor Template for FCE circuit Output circuit to activate relay to the FCE power circuit NPN transistor circuit template 0 current meter V + R sensor V ref R Pull up v be n p E n +

NPN transistor circuit template Template for FCE circuit Output circuit to activate relay to the FCE power circuit V + R sensor V ref R Pull up v be n p E n + single pole Single pole single throw contact set single throw

NPN transistor circuit template V + V ref R Pull up + circuit for PSH to activate relay FCE power supply FCE motor pressure U-Betch-um Pressure sensor Our guarantee is guaranteed Sensor is now presenting a high resistance to the transistor base circuit. v be n p E n V be is low, transistor is OFF R sensor motor running

NPN transistor circuit template V + R sensor V ref R Pull up FCE power supply FCE motor goes up + V be is low, transistor is OFF n p E n pressure V be is high, transistor is ON v be motor running not running no current is flowing in emitter-collector circuit current is flowing in emitter-collector circuit

current meter 0 N.O. push button