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Logic and overvoltage protection institutions schematic circ

2016-09-27 11:51  
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This article introduces the logic circuit diagram and overvoltage protection institution. The circuit is very simple, very cheap, but it is very effective. If you want to more thoroughly grasp the principle, you can have an idea of the circuit is the important component, such as: 2n1595, 1n3997 ,LM7805C . This circuit use the crowbar method, USES the thyristor and the supply of short circuit, causing the fuse blown. This will take place in a few microseconds or less, and provides more protection than ordinary fuse. If the output voltage is greater than 5.6 v, then the zener diode will be carried out, the switch thyristor (all in a few microseconds), the output voltage is therefore reduced to 0 volts and sensitive logic IC will be saved. The fuse will still take a few hundred milliseconds, but it is not important, because the supply circuit in zero volts and not damage can be done. Input to the controller needs a few volts dc voltage higher than the regulators. For a 5 v regulator, I recommend a transformer secondary voltage of 8-10 volts ac. 

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