The integrated circuit used in this 2002 project is not very common. It is powered directly by the telephone line, requiring no power supply.
This circuit is based on the LT1004, LT1167, LT307 or LT1490 from Analog Devices. The circuit was...
This circuit, indicated by Texas Instruments, uses a high voltage regulator and a Darlington also...
This circuit is suggested by Texas Instruments and can be used on an assembly line to drive an...