Product: 4-digit electronic clock kit (solder-and-assemble) Key benefits Hands-on learning: assemble and solder the entire 4-digit electronic clock yourself to practice soldering, circuit assembly, and basic microcontroller concepts. Ready-for-study design: built for installation and technical instruction — ideal for electronics enthusiasts and large electronics vocational schools. Reliable firmware: the microcontroller program has been tested and approved, so the clock operates as intended out of the box. Note: no electronic copy of the program (source/firmware file) will be provided. What it is and how it works Function: a 4-digit electronic clock delivered as a kit. You receive the components and must solder and assemble the device. Assembly requirements: basic soldering tools and skills are required to complete the kit. Included electronics: PCB and electronic components to be soldered and installed by the buyer (components are provided as part of the kit). Power and operation Power supply range: DC 3.7 V to 5.5 V. Battery use: the clock can run on three standard AA batteries, but ordinary 3 x AA set will drain quickly and is not recommended for long-term use. Recommended for continuous use: use a stable DC power adapter for extended or permanent operation to avoid frequent battery replacement. Compatibility and suitability Intended audience: electronics hobbyists, students, and vocational school labs for installation practice and coursework. Application: designed as an educational and functional clock module; compatible with typical low-voltage DC power sources within the specified range. Practical attributes and performance Functionality: displays time on a 4-digit electronic readout after assembly and wiring; firmware has passed inspection for correct operation. Durability and use: performance depends on quality of assembly and chosen power source; use a DC adapter for reliable, long-term operation. No firmware files provided: the installed microcontroller program is validated, but the electronic/versioned program will not be supplied. Use scenarios Electronics workshop: hands-on assembly and testing exercise for groups learning soldering, component identification, and microcontroller behavior. Vocational school classroom: repeated-build kit for lab courses where students assemble and troubleshoot a functioning clock. Practical desk clock: assemble the kit and power it with a DC adapter to use as a simple desktop time display once assembly and testing are complete. Important notes Assembly required: this is a kit — soldering and basic electronic assembly skills are necessary. Firmware access: the microcontroller program has been validated; no downloadable or electronic copy of the program will be provided. Power recommendation: use a DC 3.7–5.5 V supply for continuous use; avoid relying on ordinary 3 AA batteries for prolonged operation.