Servo Amplifier

NE544 datasheet

LM340/LM78XX Series
3-Terminal Positive Regulators
General Description
The LM140/LM340A/LM340/LM78XXC monolithic
3-terminal positive voltage regulators employ internal
current-limiting, thermal shutdown and safe-area compensation,
making them essentially indestructible.
LM7815 datasheet

LM158/LM258/LM358/LM2904
Low Power Dual Operational Amplifiers
Advantages
* Two internally compensated op amps
* Eliminates need for dual supplies
* Allows direct sensing near GND and VOUT also goes to GND
* Compatible with all forms of logic
* Power drain suitable for battery operation 
LM358 datasheet