how to make simple frequency counter

Posted on Feb 5, 2014

A very simple frequency counter circuit is shown below and can be easily built by any electronic enthusisat for the intended purpose. The circuitdiagramwas provided by Mr. Kapital through an order in Fiverr. com, I was asked to explain the functioning by him. 3. These pulses are simply the generation of positive voltages in succession at a cer

how to make simple frequency counter
Click here to download the full size of the above Circuit.

tain rate; say for example 20 positive and negative alternate voltage peaks in one minute. The capacitor and resistor values can be adjusted for adjusting the generated pulse rate. 6. Its internal circuit converts these pulses in the form of special codes (binary) and fed in a certain sequence to the decoder IC 74LS47 through its output pin no. 12, 9, 8, 11. 8. The IC74LS47 now decodes this binary information and illuminates the LED display bars in such a way that it starts displaying the numbers 1 to 9 in response to the pulses generated by the IC555, meaning, the first pulse from the IC555 displays a no. 1 over the right hand side display, the next pulse makes it display the number 2, then 3 and so on until the display reaches the number 9. 10. However the moment the right hand side display reaches the number 9, the next pulse overflows from pin 11 of the right IC74LS90 and becomes available to pin 14 of the left IC 74LS90 which now repeats the above procedure. 11. So now the left hand side begins continuing the counting by displaying the numbers 1 to 9 and we witness the ongoing counting with the displays modules together showing the number 11 until the number 99. 13. For making the counter a three digit counter or a four digit counter, simply the above stages may be added in the same pin out sequence as the two modules are connected in the given diagram. The pins of the ICs which are connected to the positive and the...

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