Capacitors are essential components in almost every piece of electronic equipment likely to be found in a home, business, or industrial setting. These passive components are used for applications ranging from hi-fi amplifiers and home cinema systems to electric vehicle (EV) chargers and power supplies in laptops.
Something else crucial to understand, is that in the case of any given application, you will very rarely find just one capacitor doing all the work.
In real circuits, engineers connect multiple capacitors together in series or parallel arrangements, or a combination of both. This enables them to achieve the precise capacitance, voltage rating, cost, or physical size a certain project requires.
So, whether you are reading this as a hobbyist building Arduino projects, or perhaps an electrical engineering apprentice or someone involved in repairing consumer electronics, it will be important for you to be well-versed in how to combine capacitors correctly.
- Parallel Capacitors: Increasing Capacity
A parallel arrangement of capacitors involves the positive terminals of multiple such components being connected to the same point, and their negative terminals being similarly grouped.
This configuration is particularly commonly used in power supply filtering or energy storage applications, where a higher total capacitance is needed.
In this kind of capacitor arrangement, total capacitance is simply the sum of all individual values. This is expressed as the formula: Ctotal = C1 + C2 + ….
The use of multiple parallel capacitors in a circuit also reduces the equivalent series resistance (ESR). This has the effect of improving efficiency and lowering heat in high-frequency circuits.
- Series Capacitors: Boosting Voltage Tolerance
When capacitors are laid out in a series configuration, this means they are connected end-to-end in a single path.
The arrangement of capacitors in series means they act as a single equivalent capacitor, with specific characteristics regarding total capacitance, voltage distribution, and charge.
Capacitors are frequently used in series for high-voltage applications, such as surge protectors or voltage multipliers. The primary benefit of this configuration is the ability to withstand a higher total voltage than any single capacitor in the series could handle alone.
Unlike the situation when resistors are used in series, the total equivalent capacitance of capacitors in series is less than the capacitance of any single capacitor in the arrangement.
The formula for working out the total capacitance of series capacitors is: 1/Ctotal = 1/C1 + 1/C2 + …. Don’t forget that various online tools allow you to quickly calculate capacitor networks in series, parallel, and combination arrangements.
3 Real-World Examples from Everyday Electronics
Let’s, then, take you through some of the “real-world” situations you may encounter for which parallel, series, or combination arrangements of capacitors might be vital:
- Power Supply Smoothing
In mains power supplies, it is common for large electrolytic capacitors to be placed in parallel after the bridge rectifier. This has the effect of increasing total capacitance, thereby translating to better ripple reduction.
- Audio Crossover Networks
Many manufacturers of hi-fi speakers use film capacitors in series with tweeters to block low frequencies. This configuration acts as a simple, first-order high-pass filter.
Smaller capacitors are often placed in parallel with larger ones to achieve precise total capacitance values, lower the ESR and equivalent series inductance (ESL), and improve the high-frequency response and audio clarity.
- High-Voltage Circuits
Across such applications as valve amplifiers and EV chargers, capacitors are often connected in series to heighten the overall voltage rating while keeping roughly similar capacitance.
This configuration ensures the total voltage is shared, so that the stress on individual components can be minimised.
Final Thoughts: Both Series and Parallel Capacitors Can Have Vital Roles to Play
In summary, mastering series and parallel capacitor combinations can greatly help solve all manner of real-world circuit problems.
This can encompass such processes as smoothing power supplies, designing audio crossovers, creating timing circuits, or increasing voltage ratings safely.