Automotive Fuse Monitor (CB26299E)

We found this simple car fuse monitor circuit in a William Sheets. The LED lights up when the fuse blows.

Siren in a box (CB7093E)
Found in Elementary Electronics from 1970, this circuit is a toy for generating different types of sound...
Inductor simulator (CB5341E)
This circuit uses an operational amplifier to simulate an inductor. The circuit is from old...
8 Digit Password Coded Lock (CB17980E)
This circuit was found in a publication in 2002 and can be powered by voltages from 5 to 12 V. The...