Found in a 90s Elektor, this mixer makes use of integrated circuits of the time. The supply must be symmetrical at 15 V.
This notch filter uses four operational amplifiers that can be 741 instead of the original ones....
This circuit is from a 1967 documentation. It makes use of varicap and diode tunnel in addition to...
This circuit generates pulses to trigger power controls with SCRs and Triacs. We found it in a...