This circuit comes from a Gernsback Publications of the 90s. The circuit uses a general-purpose transistor as a sensor. The power supply must be symmetrical.
The circuit shown in figure 1 uses the ST8R00 from ST Microelectronics which consists of a 1 A...
This is the conventional application of a 1 out of 10 decoder with CMOS 4017, as shown in an old...
We found this third-order Butterworth asymmetric filter in an old manufacturer documentation. The...