DC Circuit Design
DC circuits utilize direct current that is the flow of electrons in a single direction. It is usually produced by sources such as batteries and solar cells. When we talk about power, it is the energy utilized per unit time in a circuit. Power is measured in Watts.
Now there is a difference between alternating current and direct current (i.e. AC and DC). It all depends upon where the energy flows. Electrical current can be classified as either AC or DC. In AC, the current flows in opposite directions periodically. Electronics and electrical appliances can utilize either AC or DC circuits; sometimes utilizing both.
Where do Capacitors fit into all this?
This was important information because we will now learn about capacitors, which are electronic devices that use conducting plates, which are placed between an insulator (non conductive material). When a current flows through the plates, it causes a potential to develop between them. This means that they store energy.
If capacitors can store energy, they can release it as well. That is why capacitors are used in both AC and DC circuit applications.
Capacitor Types
Capacitors can be divided into different categories based on their design. Capacitors can be constructed and classified using different materials that are specific to their usage. For simplicity, we will divide capacitors into two categories.
Non-Polarized and Polarized Capacitors
Non polarized capacitors: these only have to do with voltage which is why they have specific ratings for voltage.
Polarized capacitors: they are known as electrolytic capacitors. The reason for this is their sensitivity to voltage and polarity (positive and negative charges).
Capacitors in DC Circuits as compared to AC circuits
We already know that the different plates of the capacitor are insulated by different materials, and they store energy, which is measured in capacitance. In a DC circuit, that has only some resistance and capacitance, the capacitor with charge until the level is the same as the voltage applied from the source.
Since there is only a unidirectional flow of current in DC circuits, the current stops flowing once the source potential has been achieved in the capacitor. The capacitor has therefore blocked the current in the DC circuit.
For AC circuits, however, it’s different. We all know that AC current changes directions, which means that the capacitor gets charged first in one direction followed by the opposite direction. When the AC current changes direction, the plates of the capacitor discharge. The current from the capacitor is said to be in phase with the AC voltage. The capacitor effectively passes the AC.
What does This all Mean?
The behavior of the capacitor with respect to the currents in both AC and DC circuits, opens up a number of practical uses for capacitors. They can be used for different ranges of frequencies, high or low, in circuits as they show different characteristics when exposed to these frequencies.
They are used in both electronic and electrical circuits. For example, they can be used to make the output from a power supply smoother. They also have their applications in coupling, filtering and decoupling circuits.
To learn more about DC circuits and how capacitors can be used in them, please do not hesitate to contact us.