Electronic Circuits Design - APS
Aim
- Using Multisim to design digital clock circuit, which should show 24 min and 60 second, like a real clock
- use the component to assemble the real circuit in breadboard.
- [extension]17 minute beeper beep at 1KHz every minute
Component
- 555
- CD4510 : decimal counter
- CD4011 : 2 in 4 NAND gate
- CD4511 : 7 segments decoder
- 4 Common cathode digital tube
Design
555
use RC Oscillation circuit to generate the 1KHz square wave
- simulate the output in Multisim Oscilloscope
CD4510
use 3 of them to divide the frequency
- clk port as input
- co port as output
- since decimal, every 10 the next get 1
Second Counter
also cd4510, use 2 and 1 cd4011
- the 2 4510 composite as a decimal
- cd4011 just judge if the first 4510 is 6(0x0110)
- get Q2 and Q3 to NAND to judge if they are both 1
- if both 1
- put output 1 to cr of 4510 and reset the 2 4510
- put 1 in the minute counter
Minute Counter
same like second counter, 2 cd4510 and the same 4011
- judge if the first is 2(0x0010), the second is 4(0x0100)
- need the first Q3, and the second Q2
- if both 1
- reset the 2 cd4510
Decoder
use each 1 cd4511 for a digital tube, great compatibility with digital tube.
- like input 4 is 0x0100(4), outputs connect to f,g,b,c are 1(High), the others are 0(Low)
Extension
judge if the minute is 17 (0x0001 & 0x111)
use 1 cd4012(4 input NAND gate)
if first Q4 and second Q2,Q3,Q4 all 1, set 1Y as 1
also the 555 1kHz input as another precondition
set the other 2 to high
if 2Y is 1
set transistor 1, then the beeper circuit works