Phototransistor Circuit. Phototransistor circuit symbol standard circuit symbols are essential for each type of electronic component enabling circuit diagrams to be drawn easily and recognisable by all. It can also be compressed logarithmically relative to the amount of incident light when voutis near voc.
For a given amount of electric current more voltage pressure is lost across a larger resistor than a smaller resistor that has the same amount of current passing through it. Voltage in a circuit with a resistor can be likened to water pressure. It is more or less proportional to the amount of incident light when vout voc.
The circuit shown in figure 1 transforms a photo current produced by a photodiode without bias into a voltage.
Phototransistors exhibit the operation of both photodiodes and normal transistors. The circuit shown in figure 1 transforms a photo current produced by a photodiode without bias into a voltage. A phototransistor just like a regular transistor has 3 terminals a base a collector and an emitter. Design fundamentals for phototransistor circuits the common emitter amplifier circuit fig.
