Having recently watched one of Fran Blanche's youtube videos I thought it would be fun to put together my own 0 to 9 counter.
Luckily, I had enough parts around including some old IC chips. The circuit is pretty straightforward:

555 timer at about 1 Hz -> SN74LS90N 0 - 9 counter -> SN74LFS48N -> CC 7 segment LED

with some LEDs: one on the clock line and one on each of the BCD lines.
While the blinking LEDS are pretty and seeing the numbers 0 - 9 is neat, it lead to a question for me:

What are the uses for this circuit as a piece of test equipment?

 

I single digit is not much use but you can cascade a number of counter stages to display as many digits as you want. You could then count items going past on a conveyor belt for example. There are many more things you could use it for.

Les.

 

Frequency or period counter or digital voltmeter (single slope easy).

Regards, Dana.

 

A FSM with 2-10 states. A 1-state machine is trivial and uninteresting.

 

Connect a sensor to the 555 - eg Sound, light, wind etc and have it affect the 1Hz .. so the scan rate will reflect the intensity of the sensor.

 

Frequency or period counter or digital voltmeter (single slope easy).

I appreciate the replies and as a result started to discover some (new to me) things. A single slope digital voltmeter has peaked my interest - is there a book which you might suggest for further reading?

 

If you google "single slope a/d" you will find several ap notes
on web discussing this architecture on web.

Regards, Dana.