Series & Parallel Capacitor Calculator

Capacitors in series and parallel

Capacitors behave backwards from resistors. Put them in parallel and the capacitances add, since the plate areas add: Ctotal = C₁ + C₂ + … + Cₙ. Put them in series and you add the reciprocals instead: 1/Ctotal = 1/C₁ + 1/C₂ + … + 1/Cₙ, which leaves the equivalent below even the smallest capacitor in the chain. Voltage splits across a series string, each cap taking its share, and evens out in parallel, where the smallest working voltage caps the whole bank. The stored energy is E = ½ · C · V². Example: two 1 µF capacitors in series come out to 0.5 µF, while the same pair in parallel gives 2 µF.

Applications: filters, flash, supercaps and DRAM

You'll find capacitors behind AC filters, the output filters of a switched-mode power supply that smooth things out after rectification, motor starters, camera flashes that dump a fast discharge into a xenon tube, and supercapacitor banks on electric buses doing regenerative braking. DRAM takes it furthest, storing each bit as charge on a tiny capacitor, billions of them per chip, refreshed thousands of times a second.

FAQ

Why are series and parallel swapped versus resistors? Capacitance tracks plate area. Going parallel adds area and so adds C, while going series acts like a thicker dielectric, which cuts C.

How do I increase the working voltage? Stack them in series. Two 16 V capacitors in series take roughly 32 V, though the capacitance drops by half. In a real circuit, add balancing resistors across each unit so the voltage divides evenly.

Can I mix electrolytic and ceramic? Yes, and it's standard in PSU design: a bulk electrolytic for low-frequency ripple with a small ceramic in parallel for high-frequency noise. The total C is basically the electrolytic, and the ceramic takes care of the high-frequency content.

What about polarity? Electrolytic and tantalum capacitors are polarized, so reversed voltage will destroy them. Ceramic, film and most of the rest are non-polar.