Voltage Level Detector (CB22135E)

We found this circuit in an English documentation from the 80's. Transistors are general-purpose types.

Light Comparator (CB18642E)
This light comparator is of the window type already explored on this website in several...
Dual 5V to 15V Converter (CB26057E)
Using the integrated circuit DCP01051D this circuit was found in the magazine Electronics Now of...
Second-order bandpass filter (CB25598E)
This filter with the operational 741 passes the frequency range between 300 Hz and 3,400 Hz. This...