12 volt relay wiring diagram

How does a 12V 5 pin relay work?

5 pin relays provide 2 pins (85 & 86) to control the coil and 3 pins (30, 87 & 87A) which switch power between two circuits. They have both normally open and normally closed connection pins. When the coil is activated, power will be switched from the normally closed pin to the normally open pin.

What is L1 and L2 in a relay?

1. The two vertical lines that connect all devices on the relay logic diagram are labeled L1 and L2. The space between L1 and L2 represents the voltage of the control circuit. 2. Output devices are always connected to L2.

What do the numbers mean on a 12 volt relay?

Numbers of a Relay

Looking at the diagram, we see the pinout of a typical 12V relay. Note that each pin is numbered. 85 and 86 are the coil pins while 30, 87, and 87a are the switch pins. 87 and 87a are the two contacts to which 30 will connect. If the coil is not activated, 30 will always be connected to 87a.

What voltage will 12V relay work?

In the datasheet, the pull-in voltage is listed as 80% of the nominal voltage. The nominal voltage of a 12V relay is 12V, so 80% of this is 12 x 0.8 = 9.6V. So in theory, this relay should activate at 9.6V.

Do relays need AC or DC?

The operating voltage of a relay is generally in DC. Small signal relays and low voltage power relays are usually in DC, but mains control relays and contactors quite frequently have AC coils. The rest of the terminals of a relay are used to connect either a AC(generally 50/60Hz) or DC circuit.

How does a 12V relay switch work?

Relays install between the power source and the electrical accessory requiring on/off power. When the relay is energized, the high current to operate the accessory flows from the power source, through the relay, and directly to the part.

Does it matter if I use L1 or L2?

It turns out they have different but equally useful properties. From a practical standpoint, L1 tends to shrink coefficients to zero whereas L2 tends to shrink coefficients evenly. L1 is therefore useful for feature selection, as we can drop any variables associated with coefficients that go to zero.

Is L2 live or neutral?

L1 is live and L2 is neutral.

What is T1 and T2 in relay?

Terminals T1 and T2 are a thermally activated contact on the resistor to indicate an overheat condition of the resistor. The contacts are normally closed and open once the braking resistor temperature reaches 120 degrees Centigrade. The minimum voltage/current for these contacts is 24VDC at .

Are all 12v relays the same?

The problem is, not all relays are the same. Many relays, if installed for the wrong application, could and will cause a short (Internal Relay Circuit) and most likely cause functionality issues or even damage to the vehicle computer systems.

What is A1 and A2 on a relay?

What Do A1 and A2 Mean on a Contactor? A1 and A2 on a contactor typically refer to either end of the electromagnetic coil assembly. Most contactor manufacturers use A1 and A2 to designate the two terminals connecting electrical power to the contactor's magnetic coil.

How do you test a 12V relay with a multimeter?

Take the leads of the multimeter and connect them across the coil terminals of the relay. For a normal coil, the multimeter should read anywhere between 40Ω to 120Ω. If the coil is damaged i.e., it is open, the meter shows out of range and you have to replace the relay.

How many amps can a 12V relay handle?

Current rating

This is the current carrying capacity of the high current circuit(s) and is normally between 25A and 40A, however it is sometimes shown as a dual rating on changeover relays e.g. 30/40A.

What causes a 12V relay to fail?

The two most common failure mechanisms of relays are contamination and mechanical wear of the internal switching elements discussed as follows: a. Contamination is a major cause of early life failures.

What is a 5 pin relay for?

5 Pin Automotive Relay

They are most commonly used to enable a low amperage circuit switch On or Off a higher amperage circuit. The most frequent example of this is the switching on of the vehicle's head lights.

How does a 5 pin switch work?

Because there are 5 parts altogether on the bottom of PCB-mounted switches, they are known as 5-pin switches. The switch is held together by four pins: two metal that enable this switch to function, two plastic ones that ensure stability, as well as a central “pin” that more closely resembles a sizable round knob.

Can we give 12V to 5V relay?

12V will definitely damage the relay board.

This 2 channel relay board requires about 200mA at 5V with both relays energized. I suppose the simplest solution would be to use a 5W, 6.8V zener diode connected in series with 12V to drop it to 5.2V.

What is 85 and 86 on a relay?

85 and 86 are the coil pins while 30, 87, and 87a are the switch pins. 87 and 87a are the two contacts to which 30 will connect. If the coil is not activated, 30 will always be connected to 87a. You can think of this as the switch in OFF.

Will 5V trigger a 12V relay?

Relays with a 5V coil can be driven by a 5V signal. There are loads of relays with 5V coils and 12V contacts. The real questions are: Do you know how much current the 5V output can deliver? Do you know how much current the AC needs?

What are the 3 main parts of a relay?

A relay contains a coil, an armature, and at least one pair of contacts. Current flows through the coil, which functions as an electromagnet and generates a magnetic field. This pulls the armature, which is often shaped as a pivoting bracket that closes (or opens) the contacts.

How do you test a 12 volt relay?

The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).

What pins to jump on relay?

If the circuit passes the high current (load side) tests, you should be able to simply jumper across terminals 30 and 87 to fire up the device.