Programmable Optically Variable Resistors: Automating the Design and Measurement of Transistor Biasing Circuits

This paper presents a solution for implementing basic electronic circuits related to the limited availability of precise resistor values. Traditional fixed-value resistors often cause deviations between desired and actual outputs. To address this, a programmable optically variable resistor (POVR) device is introduced, offering a wide range of resistance settings by adjusting input voltage. The POVR uses an optically coupled light-emitting diode (LED) and light-dependent resistor (LDR) pair to modulate resistance by varying LED light intensity, minimizing output deviations in circuit design. Additionally, the authors develop a POVR-enabled transistor bias automation system (POVR-ETBAS) for automatic resistance measurement and circuit optimization. This system provides automated circuit design and measurement functionalities. Demonstrations on common emitter (CE) mode BJT self-bias circuits show promising results in achieving desired resistance values and accurate measurements.