What is Direct Current (DC) – How it measures & works

DC direct current is an electric current that flows in only one direction. It is the type of current supplied by batteries and generated by sources such as solar panels and generators with commutators.

DC is also found in many electronic devices, including cell phones, computers, and televisions, as it is used to power semiconductors and other active electronic components. DC is easier to convert to different voltages using a device called a DC-DC converter, which makes it well-suited for use in portable and battery-powered devices.

Construction of DC current

DC, or direct current, is generated by a device called a DC generator, which is also known as a dynamo. A DC generator typically consists of the following parts:

  • Rotor: This is the rotating part of the generator that contains the magnet.
  • Stator: This is the stationary part of the generator that contains the coils of wire.
  • Commutator: This is a mechanical switch that reverses the direction of current in the coils as the rotor turns.
  • Brushes: These are conductive materials that make contact with the commutator, allowing electricity to flow from the generator.

When the generator’s rotor turns, it creates a magnetic field that induces a current in the coils of wire in the stator. The commutator, which is connected to the coils, reverses the direction of current each time the rotor completes a half-turn. This keeps the current flowing in one direction, resulting in direct current.

Working of DC current

The working of DC current, or direct current, is based on the flow of electrons from a negative to a positive terminal. In a DC circuit, electrons flow in only one direction, from the negative terminal of the power source, such as a battery, to the positive terminal.

The electrical energy is transferred from the power source to the circuit through a conductor, such as a wire. The movement of electrons through the circuit causes current to flow. The amount of current flowing in the circuit is determined by the voltage of the power source and the resistance of the circuit. The relationship between these three factors is described by Ohm’s Law, which states that the current in a circuit is equal to the voltage divided by the resistance.

How to measure DC Current


There are several ways to measure DC current, the most common of which are:

  1. Ammeter: An ammeter is an electrical instrument that is specifically designed to measure DC current. It is connected in series with the circuit, which means that the current flowing through the circuit also flows through the ammeter. This allows the ammeter to measure the exact amount of current flowing in the circuit.
  2. Clamp meter: A clamp meter is an electrical tool that allows you to measure DC current without breaking the circuit. It is equipped with a clamp that can be placed around a conductor to measure the current flowing through it. This is useful for measuring current in large and hard-to-reach wires or busbars.
  3. Shunt Resistor: A shunt resistor is a low-value resistor connected in parallel with the load. The voltage drop across the shunt is measured and converted to current. This method is generally used for measuring high currents.
  4. Multimeter: A multimeter is a versatile electrical test tool that can measure multiple electrical values such as voltage, resistance, and current. It can be used to measure DC current by setting the instrument to the appropriate range and connecting the leads to the circuit in series.

It’s important to note that in order to measure the DC current, the measuring device must be able to handle the maximum current flowing in the circuit and be calibrated.

Symbol of DC current


Advantages of DC current

There are several advantages to using DC current, including:

  1. Efficiency: DC current is more efficient than AC current when used in certain applications, such as charging batteries and operating electronic devices.
  2. Simplicity: DC circuits are simpler and more straightforward than AC circuits, as they only involve the flow of current in one direction.
  3. Safety: DC current is less dangerous than AC current because it does not cause electric shocks in the same way that AC current can.
  4. Cost: DC distribution systems have a lower initial and maintenance cost than AC distribution systems, which makes them more cost-effective for certain applications.
  5. Stable voltage: DC voltage is more stable than AC voltage and this makes it suitable for use in precision electronic equipment and instruments
  6. Easy conversion: DC current can be easily converted to different voltages using a DC-DC converter.
  7. Steady power: DC current is steady and constant, making it perfect for devices such as welding and electroplating.
  8. Solar panels: Direct current can be directly produced by solar panels, so there is no need for expensive AC inverters.
  9. Battery-powered devices: DC current is used to charge batteries and to power portable and battery-powered devices such as cell phones and laptops.

Applications of Direct Current (DC)

  • Electronic devices
  • Industrial applications
  • Power generation
  • Battery-powered devices
  • Medical devices
  • Transportation
  • Robotics
  • Automotive applications

Leave a Comment