EEVblog #742 - Why Electrolytic Capacitors Are Connected In Parallel
Why Electrical Engineering Stack Exchange recommends it
Electronics Stack Exchange users link it when asked about paralleling capacitors, since it covers lower ESR, ripple current sharing and decoupling in practical terms.
Recommended by 3 people across 3 different months, 2015 to 2018.
What it is
Dave Jones of EEVblog explains in a 'Fundamental Friday' episode why designs often wire several electrolytic capacitors in parallel instead of using one large part. He gives nine reasons, backed by the Rubycon datasheet and an LM2678 switcher example, and finishes with thermal camera tests on the bench.
What people said
Recommends guru_florida · 2015-05 · Electrical Engineering Stack Exchange · on “Where did the value of 0.1uF for bypass capacitors come from?”
Andy's explanation is beautiful and in-depth. If you find it difficult to grasp, it may help you to visualize how decoupling works in simple terms. In your mind imagine a 3D view of your board, it has a load (ICs, etc) and a power source. The load may suddenly "request" more current from the power supply however it takes time for current from the supply to reach the load over the trace distance and trace resistance. Also the built-in resistance of the supply itself or time for a switching supply to detect the new current demand and adjust (supply bandwidth) is a factor. In short, a power supply does not supply current instantly, it takes time. So imagine the load sending a message to the pow
Recommends Codebeat · 2016-11 · Electrical Engineering Stack Exchange · on “Fight inrush current with PTC, good go or not?”
I watched this video, very interesting: [this video] Deviding caps in smaller ones in parallel is good to minimize ESR and load etc.
Recommends Indraneel · 2018-12 · Electrical Engineering Stack Exchange · on “Parallel Capacitors”
Are you lucky or what??? Here's your answer [this video] Just saw this yesterday! Also, in my experience ESR drops with higher value caps, but they also have to be physically bigger (best way to guarantee that is higher voltage rating). I've never seen 2700 or 5400uF. 6800uF is more common, but then inrush current will change.
Cites ScienceSamovar · 2016-10 · Electrical Engineering Stack Exchange · on “Analyzing uC power decoupling”
I am analyzing the schematics of STM32F429 Discovery board, specifically power delivery circuit, here it is: [LINK] I have few questions that I couldn't get by myself: Capacitors C26 and C25 are tantalum capacitors(used before ADC supply pin), they are 1 uF, but on the other hand capacitors C42 and C41 are 2.2 uF and are cheap ceramic caps(they are used for internal voltage regulator). The question is - why they use tantalum capacitors before ADC? Can I plug ceramic capacitors there or aluminium electrolytic? Tantalum are expensive and many people say unreliable, basically on any forum people say something like "stay away from tantalum caps". What are implications of using ceramic or alumini