This circuit was found in February 1976, Radio Electronics magazine. The circuit is quite sophisticated using a fast-acting (thermometric) sensor and analog indicator.
This circuit was taken from recent English documentation. The circuit uses a 500 uA microammeter as an...
Found in Popular Electronics from the 90s, this circuit uses a reed switch on the rails as a...
This filter for scratch and rumble noises that occur on turntables was found in the February 1995...