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Simple Digital Counter - doc00021


The basic digital circuits are Flip Flop and Counter, both are simulated here for you to try out. This circuit can be cascaded to make even a 6 digit event counter, even a simple frequency counter can be made.

These are best done with microcontrollers today. Then what if you have to design your own microcontroller on a FPGA, so the basics have to be sound, hence you have to know what gates, flip flops and counters are.

Counter Lab.

The Counter can be tested by clicking the buttons given below, Watch the LEDs and seven segment display. Inc, Dec, and Set buttons are momentary acting and Clk Button is latching  type. The Dip Switch  in the Left also can be set by clicking on each of them, watch the switch and LEDs after a click.

a.
Set the DIP Switch as you like and then Press the Set button.  Now you will see the BCD value in the yellow LEDs named 4029 output. The Decimal value will be seen in the seven segment Display. Now try for different dip switch settings and see the BCD LEDs and Decimal output.

b.
Now Press The Inc and Dec pushbuttons and See the corresponding green LEDs which indicate the state of the Nand gate 4093 Flip Flop. Set it to Increment up-count or Decrement which is down-count.

c.
Now Click the Clk - clock or count button, the switch will latch, press it again to release.  If you toggle  it once the counter will get a single pulse and it will count it, see the BCD and decimal displays. Now  you turn it on and leave it,  the counter will keep counting one per second till you turn it off, the clock nand gate is wired to be an oscillator.




Preset Digital BCD Counter xml  use iframe part for your Webpage or Blog.

The Counter above is powered up and a power on reset cap across S4-Preset and S2-Inc is assumed, please add in your circuit. Also add 104 CD, 0.1uF ceramic disc cap to all the ICs across the supply pins. (Also add a 104 CD or 1uF cap across Inc switch and one across the Set switch for power on default settings.)

the circuit in pdf format   del00020.pdf  size 126 Kb.
the cadsoft eagle source of the circuit   del00020.zip

pdf  links may take time to load in the browser, save file target to your disk is better.

if LEDs are not lighting up, refresh the page. Tested in Mozilla 1, Opera 5 and IE5 with javascript and images enabled.

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Updated 12-Aug-14