Elektor Team (9510)

1-07-1989 | 053 AUDIO & HI-FI A vox is a voice-operated switch that is often used as a substi- tute for the press-to-talk switch on a microphone. The on...

1-07-1989 | 054 LOW-NOISE MICROPHONE PREAMPLIFIER The microphone preamplifier described is based on the SSM2015 from Precision Monolithics Inc. (Pmi), w...

1-07-1989 | 055 HIGH-VOLUME ALARM When this alarm is actuated by a low-level signal at input W, the (FiF) loudspeaker produces a number of 4-tone sequen...

1-07-1989 | 056 MAINS POWERED TIMER This timer may be inserted in a power line to provide a controllable delay before a load is energized. It was develo...

1-07-1989 | Cl D1 10n 15n 22n (loon R2 LSLK en 01...03 = 1N4148 BC547 T2 N1...N4 = ICI = 4093 R8 "Cl C8 0W5 R3 R4 00 135 057 SINGLE-CHIP MELODY GENERATO...

1-07-1989 | 058 INFRA-RED MICROPHONE The circuit of this microphone was originally designed to mon- itor a 7-segment display used on the flight deck of...

1-07-1989 | 38 059 FOUR-QUADRANT DIMMER This very special mains-operated dim- mer for domestic or industrial lights is not available in proprietary form...

1-07-1989 | 060 SENSOR SWITCH AND CLOCK One Type TL084 lc and an old quartz watch enable the con- struction of a de luxe on-off switch. Two of the four...

1-07-1989 | 18V 8A LM317 LM317 BC547 04. C5 1N4001 B1 10A * see text C1 = C2 Nom 2 47009 35V ELEKTOR ELECTRONICS JULY 1989 SUPPLEMENT 5W The circuit des...

1-07-1989 | *see text 5x iN4148 062 RADIO & TV Amateur VHF relay stations are normally actuated by a 1750 Hz call tone. This may give problems when the...