1Stainless steel cell case
2Pins · 5 mm spacing
3Outer casing (5.5 V 1 F)

Metal button or cylindrical body, “5.5 V 1 F” text, legs with polarity marks
Coin types are 1–2 cm in diameter; cylindrical types are larger

Capacitors

Supercapacitor

In simple terms

What is this?

A very big bucket; it fills and empties electricity very fast, but it does not last as long as a battery.

What is it for?

Provides short-term backup energy; when the power goes out, the clock or memory continues to work for a while.

Where do you see it?

Inside clocks and devices that keep their settings during a short power cut.

How do you spot it?

A button or cylinder body; the farad value and voltage are printed on it, with plus and minus marks.

Caution:

The voltage limit is low; it has polarity, so do not fit it in reverse and do not exceed the label voltage.

Technical definition

A capacitor with capacitance in the farads, storing energy in the double layer that ions form on the electrode surface. It charges much faster than a battery but its cell voltage is low (2.5–2.7 V). 5.5 V modules are made by connecting two cells in series.

Capacitance1 F

Voltage5.5 V (2 cells)

PolarityYes

Schematic symbol IEC and ANSI differ

IEC 60617: the drawing style used in Türkiye and Europe.

Pins 2

1Plus (+)Marked plus terminal+

2Minus (−)End marked “−” or with a stripe on the body−

Features typical

Cell voltage: 2.5–2.7 V
Module voltage: 5.5 V (2 cells in series)
Capacitance range: 0.1 F – 500 F (typical)
ESR: By type: from mΩ to tens of Ω
Charging time: Seconds, minutes
Leakage: Higher than a battery; self-discharges
Example part: 5.5 V 1 F coin type

Common mistakes

Exceeding the cell voltageA single cell tolerates only 2.5–2.7 V; give it 5 V and it is damaged. When connecting in series, the cells need balancing.

Connecting it directly while emptyAn empty supercapacitor acts like a short circuit at first and draws a large current. Charge it through a series resistor.

Thinking it replaces a batteryIts energy density is far lower than a battery’s. It suits short-term backup, not long runtimes.

Test with a multimeter

Test whether this part is good with the multimeter on the measurement screen.

Take a measurement

Where it is used

RTC and clock backup powerMemory backupStorage in a small solar-powered circuitShort-outage buffer