DIY Kits AT89C2051 Electronic Clock Digital Tube LED Display Suite Electronic Module Parts and Components DC 9V – 12V

Note
IT IS KITS ONLY. That is to say, all items are not welded on the pcb board. Buyers have to weld them on the pcb board by themselves.
ONLY for professionals. Kits assembled is not a very complex work but if you are not professional, item might get broken. We cannot offer the warranty for incorrect welding and assembling.
Features
1. Working voltage: DC 5V-12V
2. Recommend voltage: DC 9V
3. Recommend battery: CR2032 (3V)
4. Working current: 35mA
5. PCB Dimension: 90MM * 70MM
Description
1, 89C2051 digital clock kit, control chip AT89C2051, digital control using three two common male red LED digital tube display high definition brightness, because the scan is displayed, so that each digital control abcdefg each foot with a bus in parallel, change the resistance value R4-R10 can change the display brightness.
2, S1 button is used to calibrate the time, press and hold for more than two seconds to enter the calibration time status and exit quickly tap for adjusting the time value.
3, the circuit has added a 3V battery backup, power outage AT89C2051 using spare batteries, the clock does not stop, but digital is not displayed after the call backup battery out of action, AT89C2051 uses an external power supply, the digital tube display properly. So you can add a power switch, turn off the power when they go out, come back out again, the normal display, to achieve the purpose of saving electricity.
4, time accurate.