Operate the sound system switch correctly

A sound system is composed of many independent sound units, such as: tuner, deck, equalizer, LD player or VCD player and AV power amplifier. These units need to be plugged into the 220V AC power plug board. For convenience, some people turn off the power of all the plugs when they are turned off; when turning on the power, they also turn on the power when the plugs are opened. Although this method saves trouble, it has hidden dangers. Because this operation will produce inrush current and reverse peak voltage, these two impacts will often damage audio equipment. The damage of some equipment is mostly caused at the moment of starting or shutting down, and the damage is not caused when the well is in normal working condition. Inrush current: An audio equipment is composed of resistors, capacitors, inductors, transformers and other components. They are all in a cold state before being turned on. When it is turned on, its resistance value is small, so the instantaneous current is very large, which is 2.5-3.5 times the normal working current. This current is called a surge current, which can cause damage to the circuit. Inverse peak voltage: Inductive components, transformers and other units have a characteristic, that is, when a voltage is added or removed from the circuit, the unit will generate a back electromotive force to prevent the voltage from changing. Then when a voltage is applied to the inductance element when the device is turned on, it will generate a back-EMF to prevent the establishment of this voltage, but the energy of the power supply voltage is constant, so this back-EMF only serves as a voltage damping effect, and has little effect on the circuit. However, the situation is different when it is turned off. When it is turned off, a back-EMF is generated in the circuit without any barrier. This voltage is the inverse peak voltage, which is 9 times the normal voltage. Although its current is very small, but the voltage is very high, causing an impact on the equipment.

Therefore, the surge current and anti-peak voltage of each audio unit act on the audio equipment at the same time, causing a big impact, which is easy to cause damage to the equipment. In this regard, each audio unit is turned on and off sequentially one by one. The correct boot sequence is to boot in the direction of the audio signal flow: turn on the deck, CD player, LD player or VCD player, tuner, equalizer, and power amplifier in turn. The correct shutdown sequence is to turn off the power amplifier first, and then turn off other equipment. At present, for the convenience of use, a delay type power plug board has been invented abroad. One set of sockets is a direct switch socket; the second set of sockets, when this machine is turned on, can delay 1s (second) to turn on the power; the third set of sockets, when this machine is turned on, can delay 2s (Seconds) to turn on the power; the fourth set of sockets, when the machine is turned on, can delay 3s to turn on the power. Similar to this when shutting down, the power is also shut off in different time periods. This prevents the surge current and the reverse peak voltage from acting on all equipment at the same time and damaging the audio equipment.