This circuit is designed to measure very weak currents, in the order of picoamperes. We found it in an American documentation from the 80s. The integrated circuit is from that time.
This circuit uses a transistor as a sensor and operates in the range of 0 to 50º C. We found it in...
This circuit was found in a Poptronics of the 90's. The components can be changed to the desired...
In the figure we have an interesting protection bridge against power polarity inversion of a...