The given device is intended for a delay of connection of loudspeakers for the period of transition processes in UMZCh at inclusion of food and their shutdown at emergence at its exit of constant tension of any polarity.
The described device was developed for the specific amplifier with supply voltage of equal plus or minus 15 Century. In this case at emergence on one of exits of the amplifier the maximum tension, the thermal power allocated on throttles of L1 or L2 does not exceed 3 W that excludes its considerable overheat in time during which the conclusion can be drawn on malfunction of the amplifier of power (AP) and the decision on its switching off is made.
In case of emergence at the exit of UMZCh of constant positive tension the VT2 transistor opens the current proceeding via the R3 resistor (or R, VD4 (VD and a chain of R7VD the Condition of its opening in this case looks :. If tension at the exit of UMZCh has negative polarity, on R3 chain (R - VD2 (VD - R5 - VD7 opens the VT transistor
At food inclusion (the UMZCh power unit can be a source of tension) it starts being loaded (via the resistor R the C3 condenser therefore the VT4 transistor is closed and the K1 relay is disconnected. In process of charging tension on the condenser grows, the VT4 transistor starts opening and after a while (approximately 3s) its emitter current increases on so many that the K1 relay works and connects loudspeakers to UMZCh exit.
Though in the mode of protection of loudspeakers, and in the mode of a delay of their inclusion the C1 condenser is charged through the same chains, protection reaction time 10 times less as for this purpose the condenser has to change the potential to only some volt. Thresholds of operation of protection make no more than +-4 Century.
Throttles of L1, L2 limit a variable component of entrance current of an optron up to the size of the protection excluding possibility of operation. They are executed on magnetic conductors of ShL12*12 and contain on 1200 rounds of a wire of PEL-0,2 the active resistance of each throttle of 36 Ohms.
Technical characteristics of such system of protection will be very cut. The threshold of operation makes 8 Century. A maximum level of restriction of power on the protected chain at current via diodes 10 A - about 30 W. The initial power absorbed by system of protection makes about 4+4 W, maximum at current 10 A and use of the heat sink - to 130 W.
The VT1 transistor opens on VD1 chain - R5 - VD7 identical to VD6 chain - R7 - VD leads It to opening of the VT2 transistor and closing of the VT3 transistor, i.e. to shutdown of loudspeakers at increase by 8 V of supply voltage of positive polarity.