More about phone (291)

1-12-1993 | It is sometimes necessary to make a telephone conversation audible to more than one person at either end or to make a tape recording of i...

1-07-1993 | In most telephone networks, a direct voltage of 48-60 V exists at terminals a and b. When the call signal comes in, a 50-60 V alternating...

1-07-1993 | With the arrival of matched transistors in a single package it seems that the quest for the zero-noise microphone preamplifier has receive...

1-07-1992 | This receiver is meant to complement the transmitter described in the previous article. It's design Is based onjust one FET.This has th...

1-07-1992 | The proposed transmitter provides an optical(infra-red). that is, wireless, connection to a head-phone. The receiver is described in the nex...

1-07-1992 | This article is one from our 90s collection, the articles are downloadable as a PDF for all our members. Although the information we have on...

1-07-1992 | Those of you who like the telephone bell louder may find 'this circuit of Interest: It uses the telephone bell signal to actuate an 08·-...

1-06-1992 | Cellular telephones, once the symbol of people who cannot be without a telephone, are now becoming commonplace useful tools. How does the...

1-12-1991 | Rectifying the buzzer signal on a telephone line results in a voltage that may be used to switch one or more loads, for instance, a light...

1-07-1991 | Telephones are now readily and cheaply available: two identical ones and a handful of components enable a simple house-telephone to be s...