This circuit was found in an Experimenters Handbook of the 1990s. The purpose of this circuit is to keep constant the audio signal level of a system, increasing the lower signals.
Found in old documentation about neon lamps, this circuit shows how to add a simple blown fuse...
This circuit was found in a 1980s documentation. It triggers a relay when liquid from a reservoir...
For counting to values higher than 16, many 4520 can be cascaded as shown in Figure . The EN...