Digital rhythm II
Electronic
7400, 7476

We can also use digital electronics in circuits to make unusual sounds. Look at the schematic for this project. You'll notice that the output of the oscillator goes into the counter circuit instead of the speaker. The oscillator circuit generates pulses. Since digital circuits operate "on" or "off", they can make use of these pulses.

Do circuits like amplifiers and oscillators have a special term for themselves like digital circuits do?

Yes - it's called analog. Analog circuits are those we can vary continuously in some way - their volume, tone, etc. (Digital circuits, as you remember, are either "on" or "off" - there's no "in-between"!)

Now turn power ON. What do you hear from the speaker?

What are the LEDs doing?

Now press S1, S2, and S3 keys in order. What do you hear now from the speaker?

Do the LEDs change in any way?

Rotate the control volume and see what effect this has on the circuit's operation. Make some notes about how you think this project works. Before long you'll be able to explain how this works. (Remember how we asked you make notes about earlier projects? Came in handy, didn't they?)