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.

Low battery indicator (CB21619E)
Based on an Analog Devices LTC1540, this circuit consumes only 50 uA, serving to monitor the...
RIAA Preamplifier (CB919E)
This circuit should be placed between a turntable and recorder or playback media from the input to...
1.2 V voltage regulator (CB19515E)
This very low voltage regulator for 3 V input (2 batteries) was obtained in a documentation from...