Chapter 10. Experiment 10: From Sound to Light

You can now create a noise-activated LED. Figure 10-1 shows the same circuit as before, with just five components added. A photograph is included in Figure 10-2.

meme 1001
Figure 10-1. This op-amp test circuit will flash the LED whenever the electret microphone picks up sound of moderate intensity.
meme 1002
Figure 10-2. The circuit with a noise-activated LED, breadboarded (9V battery is not shown).

An LED-Transistor Combination

After the output from the LM741 passes through the coupling capacitor, it reaches the ...

Get Make: More Electronics now with the O’Reilly learning platform.

O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.

Start your free trial