The Tool Desk
Outbyte Driver Updater FREEFix the driver behind crashes, sound loss and screen glitchesFind Drivers →Outbyte PC Repair FREEClear out junk files and repair common Windows errorsFree Scan →“Capacitor memory” describes three different ideas. A discharged capacitor can show a voltage rebound through dielectric absorption; a supercapacitor can provide temporary power to a clock, volatile memory, or an embedded processor; and an experimental memcapacitor can store information in a programmable capacitance state. Only the last is a memory device in the computing sense, while the first is a measurement and circuit effect.
The right explanation depends on which meaning you have encountered. The distinctions below also matter when replacing a memory-backup component: a supercapacitor is an energy reservoir with a falling voltage, not nonvolatile memory.
Three meanings of “capacitor memory”
| Meaning | What stores the state? | Retention behavior | Typical status |
|---|---|---|---|
| Dielectric absorption | Slowly relaxing polarization inside a dielectric | A temporary voltage can reappear after discharge | Unwanted or managed circuit behavior; not data storage |
| Supercapacitor backup | Stored electrical energy | Voltage decays as the load consumes energy | Commercial hold-up for clocks, volatile memory and embedded systems |
| Memcapacitor | A programmed capacitance state | Can be nonvolatile in research devices | Emerging device research, not a drop-in consumer memory |
Why a discharged capacitor can recover voltage
Dielectric absorption occurs when polarization in the insulating material does not relax immediately. After a capacitor is charged, discharged and then left open, some of that slowly relaxing energy can raise the terminal voltage again. A meter may therefore show a “memory” of the previous charge.
What this effect does—and does not—mean
- The recovered voltage is an analogue physical effect, not a stored binary value.
- The amount and time scale depend on the dielectric, construction, previous voltage and discharge conditions.
- It can introduce errors in precision timing, integrators, sample-and-hold circuits and charge-sensitive measurements.
- A capacitor that appears discharged should still be treated as potentially energized until it is safely checked and discharged.
Can a supercapacitor keep memory alive?
Yes, for a defined hold-up interval and load. Supercapacitors are electric-double-layer capacitors that sit between conventional capacitors and batteries: they deliver high power, store more energy than ordinary capacitors, and generally recharge far more often than batteries. ISRO’s Vikram Sarabhai Space Centre describes the technology as capable of charging in seconds and withstanding more than a million recharge cycles as a general characterization, not a guarantee for every part.
#1 Best Overall
- Wide 5V-24V Input, Easy to Integrate: This supercapacitor UPS module supports 5V-24V power input and offers multiple input options including Type-C, DC jack, and 2-pin screw terminal, making it easy to integrate into different embedded and industrial power setups
- Supercapacitor UPS for Fast Charge & Long Cycle Life: Built with a 25F supercapacitor bank, this UPS board charges quickly and is designed for frequent charge-discharge use. It is a practical backup power solution for systems that need short-term ride-through instead of long battery runtime
- Backup Power for Safe Save and Shutdown: When external power is lost, the board can provide about 15-110 seconds of backup time depending on load, helping devices compatible with Raspberry Pi complete data saving and controlled shutdown to reduce sudden power-loss risks
- 3.3V Power Loss Detection Output: The onboard detection header outputs 3.3V logic when external power is present and switches to 0V after power loss, allowing the host controller to monitor power status and trigger protection logic
- Multiple 5V Outputs with High Peak Capability: The board provides 5V output through USB Type-A, terminal block, and pin header. With external power connected and the supercapacitors fully charged, it supports up to 5V/5A peak output; with fully charged capacitors only, it can provide stable 5V/3A output
What the backup circuit actually preserves
A supercapacitor can keep a real-time clock, SRAM or other volatile circuitry powered while the main supply is absent. KEMET also lists low-voltage DC hold-up for embedded microprocessor systems with flash memory. In that use, the capacitor supplies energy while the processor finishes a write, shutdown or state-saving operation; the flash itself remains nonvolatile after power is removed.
Hybrid systems commonly use a supercapacitor for repeated peak power and a battery for sustained energy. A supercapacitor should therefore be viewed as temporary power support, not as a replacement for RAM, flash or a battery-sized energy store.
Rank #2
- ◎ Supercapacitor UPS Backup Power Module: Supercapacitor UPS module with dual supercapacitors provides short-term 5V backup power to help buffer power loss for data saving and safe shutdown in SBC/DIY systems.
- ▣ Wide 5V–24V Input + Multiple Interfaces: Supports 5V-24V input via USB Type-C, DC barrel jack, or 2-pin screw terminal, making this UPS backup power board easy to integrate in different power environments.
- ⚡ Regulated 5V Output for Multiple Loads: Provides stable 5V output through USB Type-A, 2-pin screw terminal, and 2-pin header; supports 5V/5A peak (with external power & fully charged capacitors) and 5V/3A backup during outage.
- ⏱ 15–110s Backup Time for Safe Power-Off: During power failure, dual capacitors offer about 15–110 seconds backup time (depends on load and charge level), giving your device time for data saving and controlled shutdown.
- 🛡 Protection + Clear Status Indicators: Includes reverse-polarity protection and output short-circuit protection; onboard input LED, output LED, and supercapacitor voltage LEDs provide clear real-time status monitoring.
Estimating hold-up time
For an approximately constant load current, an initial estimate is:
t ≈ C × (Vstart − Vend) ÷ I
Here, C is capacitance in farads, the voltage difference is the usable discharge window, and I is load current. Real hold-up time is shorter because of equivalent series resistance (ESR), capacitor leakage, changing load current, temperature and the converter’s undervoltage threshold. Use the circuit’s minimum operating voltage—not zero—as Vend.
Rank #3
- Model: 16V
- : 15V-16V
- Features: Internal structure ,low internal resistance ,high energy.
- Size: 6.3x3cm/2.48x1.18inch
- Ideal backup power for CMOS, ,VCR ,radio, ,telephone ,smart instrumentation ,driving records ,IC three watches ,electronic watches ,LED flashlights ,LED lighting lighting ,.
What the 2026 FS Series data specifies
The YAGEO/KEMET FS Series datasheet (revision February 13, 2026) identifies these EDLC supercapacitors for low-voltage DC hold-up, including embedded microprocessor systems with flash memory. Its typical-application table covers backups of one hour or less at 50 mA or below.
| Specification | FS Series information |
|---|---|
| Maximum operating-voltage families | 5.5 V, 11 V and 12 V |
| Listed nominal capacitance range | 0.022 F to 5.0 F |
| Capacitance tolerance | −20%/+80% |
| ESR | Part-dependent; check the individual part number |
| Typical backup envelope | One hour or less, with load current of 50 mA or below |
The same datasheet warns that an abnormal surge above the maximum operating voltage can cause leakage and explosion. Supercapacitors are also not intended for ripple absorption in place of ordinary low-ESR capacitors; KEMET specifically warns against that application because of their high internal resistance.
Rank #4
- ◎ Dual Supercapacitor UPS Module: Supercapacitor UPS module with two capacitors delivers short hold-up backup power for power-loss buffering, helping with data save and safe shutdown in SBC/DIY builds.
- ▣ 5V–24V Wide Input, Flexible Wiring: Supports 5V-24V input through USB Type-C, DC barrel jack, or 2-pin screw terminal—a convenient backup power board for different power supplies.
- ⚡ Regulated 5V Output, Multi-Port Supply: Provides regulated 5V output via USB Type-A, 2-pin screw terminal, and 2-pin header; supports 5V/5A peak (external power connected) and 5V/3A backup during outage.
- ⏳ 15–110 Seconds Hold-Up Time: Typical 15-110s backup duration (depends on load and charge level) gives devices time for graceful shutdown and avoiding sudden power-off issues.
- 🛡 Built-In Protection + LED Indicators: Includes reverse-polarity protection and output short-circuit protection; onboard input/output LEDs plus supercapacitor voltage LEDs show charging and working status clearly.
Temperature and automotive examples
KEMET’s FMU automotive information describes supercapacitors maintaining a real-time clock or volatile memory when the main power system is lost or a battery is removed. It reports an operating range of −40 °C to 105 °C and a 1,000-hour test at 85 °C/85% relative humidity at rated voltage. Treat those figures as the conditions reported for the FMU information and verify the current product revision for a production design.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.How to choose or replace a memory-backup supercapacitor
- Identify the original function. Confirm whether the part supports a clock, volatile memory, processor shutdown or another hold-up task. A capacitor used for dielectric compensation or filtering is not interchangeable with a backup device.
- Calculate the usable energy window. Determine the load current, required hold-up time, starting voltage and minimum circuit voltage. Include worst-case leakage and tolerance rather than using the nominal capacitance alone.
- Check voltage margin. Select a maximum operating voltage above the circuit’s highest normal and transient voltage. Never assume that every “5.5 V” part is interchangeable with another 5.5 V part.
- Check ESR and pulse current. ESR causes an immediate voltage drop when the load starts. Ensure the resulting voltage remains above the circuit’s minimum operating voltage.
- Check leakage and temperature. Leakage can consume a substantial share of a small backup current, especially at elevated temperature. Use ratings and lifetime data for the actual environment.
- Check polarity, charging and mechanical fit. Confirm whether the component is polarized, limit inrush or charging current as required, and match lead spacing, height, diameter and mounting orientation.
Example: KEMET FS0H223ZF
Newark lists the KEMET FS0H223ZF as a 5.5 V, 22,000 µF radial EDLC supercapacitor for low-voltage hold-up and embedded-microprocessor flash-memory applications. Its nominal capacitance is 0.022 F, but that description is only a component lead—not proof that it replaces a part in your equipment. The original circuit’s voltage, capacitance tolerance, ESR, leakage, polarity, dimensions, charging behavior and required hold-up time must all match.
Quick wins for a faster PC:
Fix the driver behind crashes, sound loss and screen glitchesFind Drivers →Repair Windows errors before they cause bigger problemsFix Now →Scan for outdated or missing drivers - takes under a minuteDriver Scan →Best Value
- High Capacity & Voltage: This 16.2V 1.6.7F super capacitor module delivers reliable power with a 1.67 Farad capacity and Max 16V voltage range, making it a versatile supercapacitor for various applications.
- Safe & Easy High Current Discharge: Designed for safe and easy use, this super farad capacitor offers high current discharge capabilities, perfect for demanding power needs.
- Low Internal Resistance: Featuring an internal series structure, this ultracapacitor boasts low internal resistance and high energy, ensuring efficient power delivery in a compact package.
- Wide Range of Applications: Ideal backup power supply for CMOS, RAM, VCR, radios, TVs, smart meters, LED flashlights, motors, industrial UPS, and more. A reliable DC-link capacitor option.
- Compact Size: Measuring just 6.5x3.0x1.3cm, this bonded single capacitor supercapacitor module is compact and easy to integrate into your projects.
Supercapacitor, battery or ordinary capacitor?
| Characteristic | Ordinary capacitor | Supercapacitor | Battery |
|---|---|---|---|
| Primary strength | Very high power and fast response | High power with more stored energy | High energy for long duration |
| Backup duration | Usually very short | Seconds to a defined hold-up interval, depending on load and capacitance | Typically much longer |
| Output behavior | Voltage falls as it discharges | Voltage also falls continuously; a regulator may be needed | Relatively flatter voltage over much of discharge |
| Recharge and cycling | Very rapid and generally highly repetitive | Rapid; ISRO describes more than one million cycles as a general technology capability | chemistry- and design-dependent |
The table compares broad technology behavior, not guaranteed performance for an individual component. The correct choice follows from the required voltage window, current, duration, temperature, cycle life and available space.
What is a memcapacitor?
A memcapacitor is a device whose capacitance depends on its history and can be programmed among distinct states. In principle, the capacitance state itself carries information, unlike a supercapacitor whose voltage merely represents remaining energy.
What the 2025 HfZrO research demonstrated
A 2025 preprint by Deepika Yadav, Spyros Stathopoulos, Patrick Foster, Andreas Tsiamis, Mohamed Awadein, Hannah Levene and Themis Prodromakis reports a voltage-programmable ferroelectric HfZrO memcapacitor with more than eight stable, reprogrammable capacitance states—equivalent to 3-bit encoding—within a nonvolatile window of approximately 24 pF.
- Programming used switching voltages of approximately ±3 V.
- Reported retention exceeded 105 seconds.
- Reported endurance exceeded 106 cycles.
- Changing capacitance shifted a high-pass-filter cutoff by approximately 5 kHz.
The authors present the device as CMOS-compatible, nonvolatile analogue memory for adaptive RF filters, reconfigurable analogue front ends and neuromorphic electronics. These results describe a research-stage device, not a commercially interchangeable replacement for a 5.5 V backup supercapacitor or a conventional RAM chip.
Free tools Windows power users keep installed
One-click scans. No signup required.
Quick Recap
Common mistakes to avoid
- Calling a supercapacitor “nonvolatile memory.” Its stored energy leaks away and its voltage decays.
- Choosing a replacement by voltage marking alone while ignoring ESR, leakage, tolerance, polarity, dimensions and charging limits.
- Using a supercapacitor for ripple absorption when its internal resistance is too high for that job.
- Applying a surge above the rated maximum operating voltage.
- Assuming a flash-memory application means flash needs continuous power; the capacitor may instead be supporting a write or orderly shutdown.
- Treating a laboratory memcapacitor result as a currently available consumer component.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
