Difference between passive contacts and active contacts - News - Global IC Trade Starts Here Free Join

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This should be a term commonly used in automatic control systems (such as plc). In general, active contacts refer to an external power supply connected to one end of the contact. When the contact is closed, a high-level signal is input to the system. The contacts do not require an external power supply. The system monitors the on/off status of the contacts to determine if there is an input signal.
That is, "the active source has an output power supply, and the signal is internally passive, there is no output power supply, and the signal is externally given."
Active: It is electric. It can generate electricity. It is not only the power supply, induction, and the source is not good. Electromagnetic induction can generate electricity, arc, etc. Therefore, if there is no circuit, as long as the contact is In the above environment, it is easy to generate induction or loop power, which are active contacts.
In the case of the same voltage and the same phase polarity, it is completely different from the phase and polarity loops with different voltages.
For example, the old AC contactor (CJ1) is a pair of auxiliary normally open and normally closed. When one of the groups is connected to the high-power control loop, the other group may have a problem with the weak current, because the arc cannot be isolated. There is no wiring, but it is also an active contact relative to the weak current loop; if it is connected to the same voltage level and the same loop, the unused one is passive. This problem is common in 380V, 220V, 24V control loops. .
Another example is that in the case of flammable gas, even if the contacts are isolated, the insulation is not enough, and it is easy to discharge. The ground forms a loop. Even if there is no wiring, it is not a passive contact.
Passive contacts are the contacts that isolate and transmit and control signals in different control loops. The protection level and requirements are different in different fields. Of course, the higher the better, the environment.
Today's relays are within the safe voltage range of their insulation. Most of the unused contacts are passive contacts. However, be careful when opening and closing normally.
2. I have an example:
(1) The inverter has a switching output, one is the transistor output, we call it the active contact;
(2) There is a switch output on the inverter, and the other is the switch contact output. We call it a passive contact;
3, active contacts, such as transistor output, if the transistor does not have a power supply, this switch can not work;
4, a passive contact, such as a switch contact output, which only turns on or off the external circuit, and the power supply of this circuit does not affect the closing and opening of the contact;