This circuit simulates the effect of an inductance. Equivalent operational amplifiers can be used, and the power supply must be symmetrical. The circuit is from a 90's Poptronics.
This 1992 documentation circuit was originally designed to operate with incandescent lamps. The...
The circuit shown was found in the 1994 National Semiconductor Linear Applications Handbook. The...
The figure shows how to use a 12 V signal to trigger a TTL gate using an optical coupler. The...