Heterodyne Mixer (CB4291E)

This is a typical 80's FM radio mixer circuit. The circuit was found in a documentation of the time.

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Doorbell 555 (CB4756E)
This circuit was found in an old Poptronics but is still current as transistors can be replaced...
CK722 push pull audio stage (CB20512E)
This circuit is from a documentation from the 50's. The transistors are made of germanium. The...
Emergency Light (CB1561E)
With the configuration shown in the figure, a common 12 V lamp lights up when light no longer...