Questions about relay circuits

乐乐老了

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As shown in the picture, this is an 8-pin signal relay circuit. I would like to ask if the 4-pin is grounded, the 5-pin is connected to the positive pole of the load, and the 3-pin is left hanging. Is this wiring correct?

btty038

Do you want to ground the load? Then what is the problem?

乐乐老了

btty038 posted on 2020-7-24 11:00 Do you want to ground the load? Then what is the problem

Should pin 5 and pin 4 be connected to the positive and negative poles of the load respectively?

maychang

"I want to ask if the 4th pin is grounded, the 5th pin is connected to the positive pole of the load, and the 3rd pin is left floating. Is this wiring correct?"

I'm afraid that's not right.

The relay contacts can be connected to the positive side of the power supply or the negative side of the power supply (it is best not to connect this way), but one contact cannot be connected to the negative side of the power supply and the other contact to the positive side of the load. In this way, when the contacts are closed, the positive end of the load will be grounded.

maychang

Lele Lao Le published on 2020-7-24 11:02 Should pins 5 and 4 be connected to the positive and negative poles of the load respectively?

I guess it will become clear if you draw the power supply, load and relay contacts completely.

qwqwqw2088

Single chip microcomputer controls the on and off of the coil

Relay switch connected to load

乐乐老了

qwqwqw2088 posted on 2020-7-24 14:19 Single chip microcomputer controls the coil to turn on and off the relay switch to connect the load

Are pins 5 and 4 connected to the load?

qwqwqw2088

Lele Laole published on 2020-7-24 14:45 Is the load connected to pin 5 and pin 4?

The relay itself is a switch that connects and disconnects the load.

The high and low signals of the control coil end JD1 can open and close pins 4 and 5, and the load is connected here.

qwqwqw2088

As for the original poster's picture, he wants to ground the load, which may be connected incorrectly, or he wants to control the LED light, which I don't understand.

I still suggest that the OP understand the principle of relays. If you want to control something on and off through relays,

chunyang

Draw the relay contact circuit completely, and you should understand it after drawing it.

btty038

Lele Lao Le published on 2020-7-24 11:02 Should pins 5 and 4 be connected to the positive and negative poles of the load respectively?

btty038

Lele Lao Le published on 2020-7-24 11:02 Should pins 5 and 4 be connected to the positive and negative poles of the load respectively?

This is a pair

btty038

Your relay has two sets of contacts and can be used as one set. I don't know what you want to connect the unconnected pins to.

btty038

Relay power supply control in and out ground several groups of on and off closure connected just fine

乐乐老了

qwqwqw2088 posted on 2020-7-24 15:06 As for the original poster's picture, he wants to ground the load, which may be connected incorrectly, or he wants to control the LED light, which is a bit unclear. I suggest that the original poster understand the principle of the relay...

OK

乐乐老了

btty038 posted on 2020-7-24 16:04 Your relay has two sets of contacts and can be used as one set. I don't know what you want to connect the floating pins to.

Only one set of contacts is used because I think the two sets of contacts should be opened or closed at the same time, that is, the coil is energized and 4,5 and 8,9 are closed together. If two loads are connected, can't the two loads be controlled separately? Normally closed contacts do not control anything, but I don't know whether they should be grounded or left floating. It's my first time doing a project, and I was asked to leave a switch contact. The teacher asked me to add a relay module, but I don't know if it's right. I always feel that I should leave an IO port for the microcontroller.

maychang

乐乐老了Published on 2020-7-24 19:30 Only one set of contacts is used because I think the two sets of contacts should be opened or closed at the same time, that is, the coil is energized 4,5 and 8,9 are closed together. If you want to connect two...

The unused contacts of the relay should be left floating and should not be grounded.

In the diagram on the first floor, contacts 4, 5 and contacts 8, 9 can be considered to be acting "simultaneously" within the time range of relay action, but in fact, the actions of these two groups of contacts must be sequential, and the difference may be several milliseconds.

maychang

乐乐老了Published on 2020-7-24 19:30 Only one set of contacts is used because I think the two sets of contacts should be opened or closed at the same time, that is, the coil is energized 4,5 and 8,9 are closed together. If you want to connect two...

"If I want to connect two loads, can I control these two loads separately?"

If two sets of contacts of a relay are connected to two loads, the two loads cannot act independently of each other. However, the two loads can belong to different circuits, that is, the two loads including the power supply driving the two loads can be isolated from each other.

btty038

Control is a port, that is, the same group is closed and closed at the same time

Because the relay has only one induction coil