This circuit was found in a Popular Electronics from the 90s. The transistors are general purpose, and the gain depends on the ratio between R2 and R1.
This other photodiode amplifier uses an operational amplifier in the non-inverting mode and in the...
This circuit was found in an English magazine from 1977. The critical component is the gas sensor....
This project makes use of a technology without many digital components and that can be easily...