Best Real Time Clocks of 2025
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Real Time Clocks (RTC) are electronic devices that keep track of time even when the power is off. They are commonly used in electronic devices such as computers, mobile phones, and digital cameras. These clocks are accurate and reliable, and can be used to timestamp events, schedule tasks, and trigger actions. RTCs are available in various sizes and configurations, and can be easily integrated into electronic circuits. They are a must-have component for any electronic device that requires accurate timekeeping.
At a Glance: Our Top Picks
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Top 10 Real Time Clocks
DollaTek DS1307 Real Time Clock Module
The DollaTek DS1307 Clock is an efficient real-time clock module designed for various applications. It features a low power consumption design, ensuring that you can keep accurate time without draining your resources. With its 32K I2C EEPROM memory, you can easily store and retrieve important data, adding convenience to your projects. The clock pin provides a seamless clock signal for connected microcontrollers, facilitating smooth integration within your systems. Additionally, this module supports cascading of other I2C devices, enhancing the overall functionality of your setup.
DollaTek 10Pcs DS1307 Real Time Clock Module
The DollaTek RTC Module features a DS1307 I2C real-time clock chip combined with a 24C32 32K I2C EEPROM memory. This fully assembled module includes a CR2032 battery, making it ready for use right out of the box. It is designed specifically for compatibility with Arduino, ensuring you can easily integrate it into your projects. As a substitute accessory, it provides a reliable solution for accurate timekeeping in your electronic applications.
DollaTek 3Pcs Real Time Clock Module for Arduino
The DollaTek RTC Module is a cost-effective and precise I2C real-time clock designed for Arduino projects. It features an integrated temperature-compensated crystal oscillator for improved long-term accuracy, ensuring that you can rely on the timekeeping capabilities. With a battery input, this module continues to function even without main power, giving you peace of mind about maintaining accurate time. Additionally, its compact design reduces the number of components needed, streamlining your production process. This module is ideal for anyone needing reliable time management in their projects.
APKLVSR Real Time Clock Module with Battery
The APKLVSR RTC Module is an affordable and precise I2C real-time clock that features an integrated temperature-compensated crystal oscillator. You can set two alarms, ensuring you never miss an important event. It also monitors the power supply to detect outages, providing a reset output for added safety. Additionally, the module keeps track of the full calendar, including leap years, making it easy for you to stay organised and on schedule.
DAOKAI DS1307 I2C Real Time Clock Module
The DAOKAI RTC Module is a versatile real-time clock featuring the DS1307 I2C chip and a 32K EEPROM memory. It conveniently counts seconds, minutes, hours, days, and even months, ensuring accurate timekeeping. With a rechargeable lithium battery and charging circuit, it can maintain functionality for up to one year when fully charged, although the battery is not included. Additionally, it offers low power consumption and automatic brownout detection, making it an ideal choice for various projects.
SparkFun RV-8803 Real Time Clock Module
The SparkFun RV-8803 Clock is a highly accurate real-time clock module designed for various timekeeping applications. It features counters for seconds, minutes, hours, and even the date, making it easy for you to keep track of time. With factory calibrated temperature compensation, you can trust that your time readings remain accurate, regardless of temperature fluctuations. Additionally, the periodic countdown timer and time update interrupts help you manage tasks effectively, ensuring you never miss an important moment. This module is perfect for projects that require precise timing and flexible alarm settings.
HiLetgo DS3231 High Precision RTC Module for Arduino
The HiLetgo DS3231 RTC is a high precision real-time clock module designed for Arduino and Raspberry Pi projects. It features a dual calendar clock, allowing you to keep track of time accurately for various applications. The reset output and anti-shake input ensure reliable operation, especially in environments where stability is crucial. Additionally, its high-speed I2C serial bus (400 KHZ) facilitates quick data communication, enhancing the efficiency of your projects. With the precision of its digital temperature sensor, you can monitor temperature variations within ±3°C, making it perfect for temperature-sensitive applications.
Shutao DS3231 RTC Clock Module for Raspberry Pi
The Shutao DS3231 RTC Module offers great convenience for your Raspberry Pi projects. It operates on both 3.3V and 5V systems, eliminating the need for level conversion. With low power consumption, it provides reliable timing with both 1 Hz and 32.768 kHz outputs. You can effortlessly keep track of seconds, minutes, hours, days, dates, months, and years, ensuring accurate timekeeping until the year 2100. Additionally, the built-in digital temperature sensor enhances functionality, keeping you informed about temperature changes.
DS3231 High Precision RTC Module for Arduino
The DS3231 RTC Module is an advanced real-time clock designed for both 3.3V and 5V systems. With outputs of 1 Hz and 32.768 kHz, it provides precise timing for various applications. You'll appreciate its high accuracy, featuring a built-in digital temperature sensor with a precision of ±3℃. Additionally, the module operates within a wide temperature range of -40 °C to +85 °C, ensuring reliable performance in diverse environments. This makes it an excellent choice for projects requiring dependable timekeeping and temperature monitoring.
DS3231 High Precision Real Time Clock Module
The DS3231 Clock Module offers exceptional features for accurate timekeeping. With its dual calendar clock, you can easily keep track of time, even during power outages, thanks to the continuous timing battery backup. This module is compatible with the DS3231 encapsulation and function, ensuring seamless integration into your projects. It also provides comprehensive calendar functionalities, including seconds, minutes, hours, days, months, and years, all the way until the year 2100. This reliability makes it a perfect choice for various applications.
Frequently Asked Questions (FAQs)
1. Which has a real-time clock?
A real-time clock (RTC) is a battery-powered clock that is included in a microchip in a computer motherboard. This microchip is usually separate from the microprocessor and other chips and is often referred to simply as "the CMOS" (complementary metal-oxide semiconductor).
2. What does a real-time clock do?
A real-time clock (RTC) is an IC that keeps an updated track of the current time. This information can be read by a microprocessor, usually over a serial interface to facilitate the software performing functions that are time dependent.
3. Can a real-time clock be used as a system clock?
In some references, the term real-time clock is interchangeable with the term system clock . Within the context of this book, however, these terminologies are separate, as they are different on various architectures. Real-time clocks exist in many embedded systems and track time, date, month, and year.
4. What is the difference between real-time clock and system clock?
A key difference between an RTC and the system clock is that RTCs run even when the system is in a low power state (including "off"), and the system clock can't. Until it is initialized, the system clock can only report time since system boot ... not since the POSIX Epoch.
5. What are the benefits of real-time clock?
Benefits of RTCs include: RTC ICs have proved to be more precise than other methods — like programming the timer of the controller. It frees the main system from time-critical tasks. It has low power consumption and improved frequency stability.
During our real time clock research, we found 26 real time clock products and shortlisted 10 quality products. We collected and analyzed 4,759 customer reviews through our big data system to write the real time clocks list. We found that most customers choose real time clocks with an average price of £11.43.
The real time clocks are available for purchase. We have researched hundreds of brands and picked the top brands of real time clocks, including DollaTek, APKLVSR, DAOKAI, SparkFun, HiLetgo. The seller of top 1 product has received honest feedback from 643 consumers with an average rating of 4.9.
Harvey Wall was born and raised in Norwich. He mastered the art of tool production and finished at the prestigious Norwich University. His area of interest include cutting tools, abrasive finishing and power tools. Harvey is always looking for ways to improve the finesse of industrial tools via his myriads of researches. He also shares some of his experiences on many platforms while writing on tool products.