2N3904 Transistor Circuit: How to Amplify 0.5–5V Sensor Signal from 1mA to 10mA?

A pressure sensor outputs a voltage range of 0.5 V to 5 V with a current of about 1 mA, and the goal is to amplify the current to approximately 10 mA using a 2N3904 transistor powered by a 9 V supply. The main challenge is selecting appropriate resistor values for the transistor circuit. A recommended solution is to use an operational amplifier (op-amp) in a buffer configuration (unity gain) to provide the necessary drive current without altering the voltage signal. A single-supply, rail-to-rail op-amp powered by 9 V is suitable, especially if the sensor output does not reach ground level. For precision applications, choosing an op-amp with low input offset voltage or offset compensation is advised. The discussion clarifies that "amplify current" means increasing the output current capability from 1 mA to 10 mA while maintaining the voltage signal. Further details on resistor calculations for the 2N3904 transistor were not provided, but the op-amp buffer approach was confirmed effective by the original poster.
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