This circuit was found in a National Semiconductor manual from the 1980s. The integrated circuits used are equivalent. Note the need for a symmetrical power supply.
Found in old American documentation, this filter has a 8 dB per octave attenuation. The formulas for...
This version of a call-fish is from 1981 using, for this reason, a 90 V battery that is no longer...
This circuit is from an old Electroics Now. Its purpose is to protect the fax and modem lines of...