Symmetric 50 mA Regulator MC1568L (CB15327E)

The LM1468L can also be used. The circuit is from Motorola's Linear Interface ICs and the components are not very common today.

Increasing the voltage of a fixed regulator (CB8476E)
Found in a 90s Electronic Design, this suggestion to have a higher voltage in a fixed regulator...
VCO operational (CB9436E)
Found in Fairchild documentation from the 90s, this circuit generates signals with the...
PWM with 555 (CB11853E)
This circuit is intended for PWM speed control of a motor up to 500mA, using integrated circuit 555....