Quick Answer

Question How many amps does a 12V relay draw?

Current rating

The current draw of the coil is not normally shown but is typically 150-200 mA with a corresponding coil resistance of around 80-60 W.

How many volts can a 12V relay handle?

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.

At what amps do you need a relay?

Most automotive relays are at least 30A (check the specs to make sure). This means they can transmit 30A without issue. The fuse holder you are looking at, however, cannot handle that much amperage.

What are 12 volt relays used for?

In 12-volt automotive circuits, even small resistance amounts can cause significant voltage drop. Relays provide a solution by shortening the required length of the heavy-gauge, power-delivery wire from the battery or alternator to the load.

Will a 12V relay work with 5V?

You cannot activate a 12Vdc relay with 5V.

Why use a relay instead of a switch?

Relays can reduce the need for high-amperage wiring and switches, which are expensive and take up space. Therefore, switching to relays in your electronic systems can reduce the size or weight of a casing, for instance, or allow manufacturers to fit more functionality into a space of the same size.

What is the resistance of a 12V relay?

The relays are usually supplied with 12 V directly from the vehicle battery. The electrical resistance (impedance) of the coil is vary and is different depending upon the manufacturer of the relay as well as relay’s type, but in general a typical value should be expected between 50 ohms and 200 ohms.

What is the difference between 5V relay and 12V relay?

What is the difference between a 12V relay and a 5V relay? The voltage ratings are what the coil needs to energize properly. The 12V coil will likely have a higher resistance than the 5V coil. Coil resistance, voltage and current are completely independent from the relay contact ratings.

Does a relay increase voltage?

Nonetheless, relays can “control” larger voltages and amperes by having an amplifying effect because a small voltage applied to a relays coil can result in a large voltage being switched by the contacts.

How much current is required to switch a relay?

The coil of a relay passes a relatively large current, typically 30mA for a 12V relay, but it can be as much as 100mA for relays designed to operate from lower voltages.Coil resistance.

Relay coil current = supply voltage
coil resistance

Are all 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.

Does a relay need constant power?

The answer to that one is No. Relays have finite life time in terms of how many times they can open and close. And limit to how much current they can handle.

Is a relay the same as a fuse?

A fuse is a one time protection device that can interrupt a circuit. A relay is a device that is used to connect or interrupt the circuit.

Do 12V relays get hot?

It is normal for the relay coil to be slightly hot during normal operation, but if the contacts are hot, it means that the service life of the relay has expired and should be replaced.

Can you use a 12V relay for 24V?

A trick I have used is driving two 12V relay coils in series on a 24V rail. Then there are other options such as a ballasting resistor, diodes to drop voltage, and even a regulated 12V rail. It’s a lot easier to use 12V coils in a 24V system than the other way around…

Can you use a 12V relay on a 6v system?

Description. This circuit allows a 12v relay to operate on a 6v or 9v supply. Most 12v relays need about 12v to “pull-in” but will “hold” on about 6v.

Can 5V used for 12V?

A 5V adaptor cannot drive a 12V device. Also, an adaptor of voltage higher than the device needed would damage your device.

Do you have to use a relay with LED light bar?

So in short if you do not properly wire the light bar to a battery and use a correct amperage switch which will keep the light bar on it’s own independent circuit a relay is unnecessary. However if you tap into the high beams or another lower voltage switch then you will need a relay to avoid an electrical fire.

Is a relay needed for LED lights?

A relay is an electrical device that changes the flow of electricity. It does this by using less electricity than there is in a circuit for high current. Without a relay, LEDs do not work. Without the light, the light does not work.

Why are relays needed?

Relays are used where it is necessary to control a circuit by a low-power signal (with complete electrical isolation between control and controlled circuits), or where several circuits must be controlled by one signal.

How do I activate my 12V relay?

Connect the relay’s common terminal to your battery supply, which could be the same supply providing power to the coil. Finally, connect the equipment’s power lead to the normally open terminal of your relay. When you use the relay, the contact will then put the voltage on your pin.

Can a DC relay be used with AC?

In theory, then, AC can be used to operate a DC relay. In reality, however, doing so is impractical. Since alternating current decreases to zero every half-cycle (120 times per second for 60 cycle voltage), the relay armature tends to release every half-cycle.

Does a relay control voltage or current?

A relay is an electromagnetic switch operated by a relatively small electric current that can turn on or off a much larger electric current. The heart of a relay is an electromagnet (a coil of wire that becomes a temporary magnet when electricity flows through it).