74HC393 Binary Counter

The 74HC393 is a widely used ic chip. Its main function is as a binary counter. A binary counter is similar to a Decade counter such as the well known 4017 Johnson counter, but the 74HC393 counter functions slightly differently (as you will see next).

The 74HC393 is a 14 pin dual binary counter ic chip, each counter contains a 'Clock', a 'Reset' and four outputs. The first counter involves pin 1-6, the second counter uses pin 8-13

Pin 1 & 13 are the two 'Clocks'. The 'clock' is the input for its counter (not the whole chip).

Pin 2 & 12 are the two 'Resets', the 'reset' tells the counter when to stop and reset. The 'reset' is active-high meaning it only resets if the signal to it is high.

Pin 3-6 & 8-11 are the outputs, these are the pins where the processed information comes out the chip.

Pin 7 is ground.

Pin 14 is power (5v)

Remember, the two counters won't interact with each other unless you connect them, and this is a binary counter so there aren't ten decoded outputs.

The datasheet for the chip (by Texas Instruments) is below:

To demonstrate how the Binary counter functions, I have put together a simple circuit that will use one of the two counters and run its simplest counting combination (Binary).

The ' Clock' will receive input from a 555 timer running in astable mode emitting a frequency of around 2.2Hz, just enough for you to catch the outputs of the counter without it moving onto the next one, though the frequency can be adjusted by twisting the potentiometer. The circuit will be fully automatic but will include a manual reset button. The circuit diagram shows everything so you don't have to follow the breadboard footprint, unfortunately, I did not have the footprint for the 74HC393 chip so I had to make my own.

In this circuit, you will need:

1x 555 timer

1x 74HC393

1x 10k potentiometer

1x 22uf capacitor

1x 10k resistor, 1x 680ohm (or around 680) resistor R1=680, R2=10k

1x push button

4x LED

And a 5v DC power source (USB will work fine), a breadboard and some jumper wires.

Once you finished assembling the circuit, plug the power source in!

What you should see is the LEDs flashing randomly. They aren't flashing randomly at all, in fact, they are displaying numbers, the counter is just counting from 0 to 15 in binary and what you are seeing are our normal numbers in binary format. There is the binary number table from 0 to 15 here.

This is the very basic purpose of a binary counter (to count in binary), but there are way more uses for the 74HC393 chip. Most circuits involving a decade counter can be replaced with a binary counter such as this one.

I will post a proper big circuit using the 74HC393 here soon but for now, a demonstration circuit for the chip will do.

If the circuit does not work check the following:

- The direction of polarised components

- Small wiring issues

- The power source

- The chips (if they work or not)

If none of these solves the problem, try building the circuit again.

Any questions or suggestions will be appreciated in the comments!