Voltage to Current Convertor When driving the input (base) of a transistor gain stage:
you must convert the input voltage to a current by using
a voltage to current convertor
--a resistor.
Current to Voltage Convertor When deriving a voltage from the collector of a transistor amplifier
stage: you convert the output (collector) current into a voltage by using
a Current to Voltage convertor in the collector circuit--you guessed
it--a
resistor.
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