Voice relay

I offer the simple acoustic automatic machine for turning on of various actuation mechanisms. The essence of work of the circuit (fig. 1) consists in the following. At a certain level of acoustic noise near the high-sensitivity BM1 sensor microphone, threshold which level of inclusion is established by the tuning R1 resistor, the signal strengthened by the operational DA1 amplifier arrives on a transistor key of VT1-VT2 which submits a food on the K1 relay. The relay the contacts (on the circuit they are not shown) closes a loading power-supply circuit. After the termination of noise loading is switched off.

is used This way by p in microdictophones which automatically join in a record mode in the presence of a sound signal. This circuit is used by me for automatic inclusion of UZCh of the on-door speakerphone. This circuit will well serve p as

in the lighting machine gun. Then it is necessary to add it with the terminal cascade with a switching off delay on 3... 4 minutes. If to establish such machine gun, for example, in a hall, light will automatically light up in the presence of the slightest noise (an opening door or a voice) and to die away after the lapse of several minutes at a complete silence.

In an initial condition both entrances of a chip of DA1 are in an equilibrium state, and on base of the VT1 transistor very weak signal, about several millivolt insufficient for opening of the transistor arrives. At sound impact on a microphone the alternating voltage moves on an entrance of 2 OU. Repeatedly strengthened signal from a conclusion of 6 OU, still strengthened by the VT1 transistor, gets on an electronic key on the VT2 transistor which, in turn, switches the actuation mechanism - the K1 relay.

and R2 depends On face values С5 a delay of switching off of the relay at loss of sound impact on a microphone. If the delay is not necessary - these elements exclude from the circuit. When the big delay of switching off is necessary, face value С5 should be increased. At the face values specified on the circuit, the switching off delay at a food of the circuit 12 In will make 1 mines ±10 %. If capacity of the C5 condenser to increase to 2000 мкФ, the switching off delay at the same supply voltage will increase till 10 minutes. However in the latter case accuracy of time of endurance is lost and dependence on duration of initial impact of sound fluctuations on a microphone increases. the VD1 Diode serves p as

for elimination of a tinkling sound of contacts of the K1 relay. К1 - the low-power relay of the type RES10, РЭС15 on tension of operation 9... 11 V.Dlya of a kommutirovaniye of powerful chains of loading with big supply voltage are necessary to observe security measures and to use the relay with the corresponding admissible current through contacts. The microphone of BM1 represents a cap of DEMSh or similar with resistance of a winding 200... 250 Ohm and above. Good results turn out when using as a microphone of an elektretny cap of MKE of various updatings (earlier it was used as the built-in microphone of cassette tape recorders).

For elimination of aimings and other hindrances a microphone is necessary for connecting to the device a short ekranirovanny cable the in length no more than 20 see. At rigid fastening of the case of the device to other designs (for example, to a vertical wall) it is necessary to wrap up a microphone cap foam rubber and not to screw on the device case that hindrances at various blows (for example, hlopaniye of the next door) did not influence a microphone.

as VT2 can use silicon transistors of average capacity КТ603, КТ630 or their analogs with any alphabetic indexes. As VT1 will approach КТ361 with any alphabetic index.

device Correctly assembled from serviceable details practically does not need control. It is necessary to pick up only the tuning R1 resistor a threshold of operation of the device.

белые диваны

Author: А.КАШКАРОВ, St.-Petersburg