Description:

1. This product is a 24-hour digital circuit clock, using CD4518, CD4511, CD4081, CD4013, CD4060 and other chips. The circuit does not contain a microcontroller, so there is no program. The hours, minutes and seconds can be adjusted, and it does not have an alarm clock function. This kit is mainly composed of a second signal generator, a counter, a decoding display, and a timing circuit. The second pulse is accurately divided by the high-frequency signal generator to obtain a 1HZsquare wave signal, and the timing is relatively accurate.
2. The second signal generator consists of CD4060 and CD4013, which generates asquare wave signal with a frequency of 1HZ. CD4060 is a 14-level binary frequency divider/oscillator. It forms a 32768HZ oscillator with external resistors R44, R43, C1, C2 and Y1. After 14 levels of binary frequency division, asquare wave signal with a frequency of 2HZ is obtained at pin 3. CD4013 contains two independent D flip-flops. One of the flip-flops is configured as a binary counter through wiring. The second signal can be obtained by binary counting the input 2HZsquare wave signal. CD4518 is a double decimal adding counter. Use three CD4518s to time the hours, minutes and seconds. The hours are configured in 24-digit format, and the minutes and seconds are configured in 60-digit format. The counting result of CD4518 is output from pins Q0-Q3 to BCD decoder CD4511 in the form of BCD code. CD4511 converts the BCD code into a display segment code that lights up the corresponding digital tube, forming recognizable Arabic numerals on the digital tube, which is intuitive Displays the current timing result.
3. The minutes and seconds are counted in base 60. The seconds signal is introduced to the EN terminal of CD4518 through switch S1, and 1 is added at the falling edge of each second signal (if the second signal is connected to the CLK terminal of CD4518, it is added at each falling edge of the second signal). The rising edge of the second signal adds 1. When the counter counts to 9, Q0-Q3 outputs 1001, that is, Q3 is 1. Since it is a decimal counter, when the next second signal arrives, the counter changes from 9 to 0, and Q0-Q3 outputs 0000. , thus forming a falling edge signal on Q3. This signal is introduced into the tens counter of the seconds counter. Every time the ones counter reaches 10, the tens counter increases by 1. When the tens counter value reaches 6, Q0-Q3 output 0110, that is, Q1 and Q2 are 1 at the same time. The output 1 of Q1 and Q2 is connected to the reset terminal of the counter through an AND gate, causing the counter to count from 6 to 0 in advance, completing a hexadecimal counting cycle. The reset signal is also used as a The counting signal of the minute counter, the minute counter increases by 1 every 60 seconds. The minute counter is also in base 60. When the minute counter reaches 60, the tens digit of the minute counter also sends a reset signal through an AND gate, causing the hour counter value to increase. 1. When the counter reaches 24, Q0-Q3 of the tens digit is 0010 and Q0-Q3 of the ones digit is 0100. By doing the AND algorithm of Q1 of the tens digit and Q2 of the units digit, they are connected to the reset terminals of the two counters. Make the hour digit count return to 0 after reaching 24, realizing 24-digit counting.

Specifications:

Product power supply voltage: 4.5V-5.5V DC Product size: 129.2CM*7.86CM DIY component weight: 85 grams

Note: This is an unassembled kit, you will need to solder. The shell is an optional version, select the with shell option if required.

There is a yellow protective film on the outside of the shell, which is used to protect the shell from wear and tear during transportation. Please tear off the protective film when using it.

Package Include:

1x PCB board 6x 0.56 digital tube 1 bit common cathode 2x 470 ohm resistors 50x 1K resistors 3x 2.2K resistors 1x 100K resistor 1x 10M resistor 4x 1N4148 diodes 3x 103 monolithic capacitors 1x 32.768KHZ crystal oscillator 2x 30P ceramic capacitors 1x 25V 100UF capacitor 1x KF301-2P 2x 665 buttons 1x 12D07 toggle switch 5x 3MM LED red hair red 10x 16P IC holder 2x 14P IC holder 6xCD4511 3x CD4518 1xCD4081 1xCD4060 1xCD4013