Linear Ohmmeter LM11 and TL431 (CB14548E)

We found this circuit in Motorola's Linear Databook in 1990. Integrated circuits are somewhat difficult to obtain today.

SST LLE Series Liquid Level Sensor Switches
SST LLE Series Liquid Level Sensor Switches Available through Mouser Electronics, these solid...
Melody Generator (CB19822E)
Texas Instruments' TMS1000 integrated circuit was very successful in the 1980s, consisting of a...
Series regulator (CB8827E)
This circuit is based on a regulator component that consists of a transistor and zener in the same...