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 circuit was suggested by Texas Instruments in a manual of operational amplifiers. Other...
Found in American documentation from the 1980s, this circuit shows how to use an LM3909 pulsator in a...
This circuit was found in an Elektor from the 90s. The integrated circuits are not very common...