The circuit shown in the figure below is from the 1993 Linear Technology Applications. The operational ones used are uncommon and the use of equivalents can be analyzed.
This circuit is from a documentation on Motorola interfacing techniques from 1975. The Darlington may be...
This circuit is from an old Electroics Now. Its purpose is to protect the fax and modem lines of...
This 8-channel converter was found in a 1970s American documentation. The integrated circuits used are...