Found in Electronics now from the 90s, this circuit uses a sensor from the time, which is difficult to find today. The circuit activates a sonalert-type buzzer.
This preamplifier appears elsewhere in this section and this version was found in American...
This 2000 circuit, found in the documentation of the time, is intended for charging this type of...
Based on the well-known LM3909, this LED pulser circuit was found in American documentation from...