Found in old documentation, this circuit is tuned to pass signals below 245 Hz with a level of 0.044 dB above 500 Hz.
This sensitive motion sensor with inductive sensor was found in a 90s Elektor. The circuit uses only...
This simple balance indicator for sound equipment was found in a 1982 documentation. The M1...
This circuit was found in a 1992 documentation. It uses a photo diode as a receiver and an...