How are latching and normal relays different? This comparison of latching relay vs. non latching relay types has all the answers. Read it to understand not only the differences between the two types of relays, but also the advantages and disadvantages of each, and where to use which type of relay.
What is a Latching Relay?
A latching relay is a type of relay that has two stable states and can store the state even after being de-energized. It behaves like a switch, allowing you to control a circuit with just one signal.
When the coil of this relay is energized, it either opens or closes contacts depending on its initial state. To change the contacts’ state, the coil has to be energized again.
What is a Non-Latching Relay?
A non-latching relay, on the other hand, does not store its state when de-energized, like a latching type relay does. Instead, it returns to its original state, which can be normal open or normally closed state.
This type of relay requires two signals in to control a circuit; one signal to open the contacts and another to close it. It’s, therefore, typically used in systems where there is a need for temporary control of the circuit.
Latching Relay Vs. Non Latching
While both latching and non-latching relays serve the same purpose, they vary in terms of working and features, they, therefore, each suit different applications. Below is a comparison of latching relay vs. non-latching relay, highlighting the pros and cons of each type:
Latching Relay Meaning
The first difference between relay and latching relay is its meaning. A latching relay is called so because it latches onto certain states or positions when the coil is energized. It has two stable states and is capable of storing its state even after being de-energized.
A non-latching relay, on the other hand, is not capable of storing its state and requires two signals to control a circuit; one signal to open the contacts and another to close it.
Latching Relay Working
A latching relay works like a switch, allowing you to control a circuit with just one signal. When the coil is energized, it either opens or closes contacts depending on its initial state. To achieve that, the latching relay operation includes a latching mechanism, which could be a mechanical gear lock or magnetic force.
In contrast, a non-latching relay requires two signals to control the circuit; one for opening the contacts and another for closing them. It doesn’t store its state and quickly returns to its default position when the coil is de-energized. This type of relay is, therefore, built as either normally open or normally closed.
Latching Relay Power Consumption
Needless to say, a latching type relay consumes less power than a non-latching type. This is because latching relays are capable of storing the state even when energized, thus reducing the amount of energy required to keep the relay in its current state.
Non-latching relays consume more power since they must remain energized for the entire duration that the circuit needs to remain open or closed. That means more energy is needed to keep the relay in its current state.
Latching relay Noise Levels
The latching relay operation is noiseless. That’s because it only uses electrical energy when switching. This type of relay is, therefore, preferred when working with some electronic equipment that requires low noise levels. Also, in households or offices where noise is an issue, these types of relays are preferred.
On the other hand, non-latching relays can produce a buzzing noise when they remain energized for too long. This makes them unsuitable for applications where noise levels must be kept low.
Latching Relay Applications
The latching relay switch is an invaluable device in many different applications. You can use it in all sorts of controls, ranging from automotive to industrial automation and consumer electronics. Some of the most popular applications include switching light bulbs, controlling motors, providing a timer delay circuit and so on.
Latching relay applications mostly include situations where power consumption is paramount or systems where a single signal is needed to control the circuit. Latching relays also find useful application where keeping the relay circuit energized for long hours could cause overheating issues.
Non-latching relays are also widely used. However, they do not perform as well in some applications due to their higher power consumption. These types of relays are usually preferred for applications where a short time delay is needed, such as in timers and security systems.
Latching Relay Price
The latching relay price is usually on the higher side than that of a non-latching relay. This is mostly due to its complex design, which needs additional components like latching mechanisms and springs.
Non-latching relays, in comparison, are cheaper because they are simpler in design and need fewer components. However, that also depends on the relay’s complexity, size, and other features.
Latching or Non Latching Relay?
It depends. The decision between latching relay vs. normal relay should be made based on the application’s requirements. For example, if power consumption is an issue and noise levels must remain low, latching relays are the way to go.
However, for situations where a short time delay is needed, non-latching relays might be more economical. That’s because these relays generally cost less.
Ultimately, it is up to the designer to decide if a latching or non-latching relay is needed, and how to implement in the system. Depending on the application, there may be more than one type of relay that could work. Therefore, careful consideration must be given when making the choice
Both latching and non-latching relays have their own pros and cons. So it helps to have a deep understanding of these two types of relays before making a decision. As mentioned above, the choice between latching relay vs. non-latching relay should be made based on the application’s requirements. Therefore, assess all factors before arriving at a conclusion.