In this interesting circuit from Popular Electronics, the output voltage is the square root of the input voltage. Equivalent operational amplifiers can be tried out.
This 15 V regulator uses the integrated 100 mA L series. The circuit was suggested by Motorola's Linear...
This 1992 circuit operates in the range of cordless phones used at the time. The circuit is based...
We find this circuit in the manual of the used integrated circuits. The manual is from Linear...