More about phone (291)

1-12-2003 | This circuit produces a ringing sound similar to that made by more recent telephones. It consists of three almost identical oscillators conn...

1-12-2003 | The ‘FM Remote Control Receiver’ has a connector where an analogue output is made available. To make a simple intercom or P.A. system the as...

1-12-2003 | A number of years ago (November 1997), we published a design for a stereo microphone preamplifier with balanced inputs and a phantom power s...

1-11-2003 | The directional microphone published in the July-August 2002 issue of Elektor Electronics does its job, but does not have the right directio...

1-10-2003 | It is not just power amplifiers that can deliver the much sought-after warmth of the ‘valve sound’ — headphone amplifiers can too. What is s...

1-10-2003 | Most commercial preamplifiers and power amplifiers have a headphones output. However, because of its simplicity the sonic quality of such an...

1-09-2003 | In spite of alternatives based around the Internet, SMS and e-mail, the good old DTMF remote switch still has its place, and, thanks to the...

1-07-2003 | A fieldstrength meter is all you need for a quick go/non-go check on the transmitter section (TX) in a GSM phone (900 MHz or 1800 MHz), a DE...

1-07-2003 | Here is a very simple, inexpensive and interesting project which provides lot of fun to a home experimenter or hobbyist. This simple transmi...

1-04-2003 | Commercially-produced subsonic microphones are too expensive for the cost-conscious user. However, as long as a high-precision measuring dev...