The field of electronics is lifeless without current sensing circuits. Different electronics need current sensing systems for their efficient performance. Or else technical faults, short circuits, electrical fires, and complete failure can take place if there is slight negligence in current sensing.
So what exactly is a current sensor? Well, to not confuse you for this, we can define a current sensor as a mechanism for detecting the current in wiring and indicating its value no matter whether it is high or low. Now, the value given by a current sensor can be used by an ammeter for further filtering down to gain an accurate value as per the experiment or the application. The current sensors are complex and include different small circuits as well.
These sensors are available in a variety of types in the market. Different domains, like automotive, use current sensors for multiple applications. It’s time to quickly check out the principle of current sensors.
So that you can have a clear idea about how this mechanism works in major applications right from the beginning!
Principle of Current Sensing Circuits
The current sensor is not only for detecting the current. There is more to its role. It is also important for transforming the current into a voltage that has a direct relation with the current itself.
When the current flows, it will decrease the voltage along the route from which the current is flowing at the moment. The conductor that contains the current also produces a magnetic field in the system. So these are the things that you need to keep in mind while constructing a current sensor.
Current Sensing Element or Sense resistor
Current sensing means that the system produces a voltage signal as per the current in the circuit. One common way to sense this current is to rely on a resistor and place it in the way of the current. Use a series arrangement for this so that you can keep the resistors almost anywhere in the current’s path. It means you can also call a current sensor a current-to-voltage converter.
Factors affect the functions of Current Sensing Circuits
· Low Values to lessen power failures:
The values that you obtain from the current sensor directly relate to the threshold figure. The threshold value for such a circuit depends on the sensed data of the current.
· Low-temperature coefficient:
Temperature is another factor that influences resistance. In order to maintain accuracy, you need to focus on the temperature. If a resistor’s resistance is near 0, it means you can use it for your experiment. The power is also variable at different temperature ranges. However, you cannot ignore the peak power, and due to this, you need to keep monitoring the energy graph as well.
Advantages and Disadvantages of Current Sensing Circuits
Pros:
- Current sensing resistors are affordable
- These offer impressive precision
- The current ranges from low to medium
- It can also detect AC and DC
Cons:
- It might interact with the resistance of the circuit flow, which can boost the output resistance leading to faulty loading.
- Excessive power loss due to dissipation.
Procedures of Current Sensing Circuits
1. Direct current sensing:
- This type of sensing follows Ohm’s law.
- You need to use a shunt resistor with a load when constructing the circuit.
- After this, it will produce voltage through the shunt resistor.
- This voltage will be in direct relation with the current.
- You can use different amplifiers to determine the shunt’s voltage.
2. Indirect current sensing:
- Indirect current sensing follows Ampere’s and Faraday’s Laws.
- You need a loop across the conductor that carries current.
- It will induce voltage for the loop that directly relates to the current.
- You can only use this indirect sensing for currents ranging from 100A to 1000A.
You can perform indirect sensing by two more methods. These are low-side current sensing and high-side current sensing. So let’s see what are the differences between their work below:
3. Low-Side Current Sensing:
- The voltage of this type of current sensing is low in input.
- You merge the resistors of the load and the ground together.
- The low side current sensing is a common mode voltage which means it supports near the ground.
- Therefore, it is reliable to use for rail-to-rail input and output for OP-AMPs if you are using any.
- You need to ground the resistance while the load works with the supply.
- However, this type of sensing can interfere with the load’s functioning and potential.
4. High Side Current Sensing:
- It works by joining the resistors of the power supply and the loads of the circuit.
- It is useful because it detects the current of the power supply, which helps in the prevention of the defects of a load like load shorts.
- The input of the amplifier should have a similar range as the load’s voltage.
- You need to ground the load after this, and you will obtain the sense current through it.
Current Transformer (CT):
A current transformer (CT) is a device that determines a certain amount of current for you. Different producers love CT because these offer brilliant performance for the high current applications.
It has the ability to determine huge amounts of current without using much power. It is a complete power saver when it comes to its job and can be a multipurpose device for determining voltage as well.
However, it is important that you perform every step with undivided attention to prevent any chances of mishaps and complications. Or else, you can end up ruining the circuit, and it would fail to give you desired results as well.
Summary
The range of creativity with a current sensor is limitless. You can use it as per your needs to never fall short of producing highly efficient tech electronics and the latest gadgets. Different technologies instill remarkable features in current sensors, like precision and efficiency.
We hope that this discussion rendered some interesting facts before you regarding current sensors. Now that you know how current sensors work, it’s time to give them a shot for your upcoming projects!
