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--- tamiwiki:projects:piezo [2023/11/25 13:41] – yair
+++ tamiwiki:projects:piezo [2023/11/26 08:21] (current) – [more] yair
@@ Line 9: / Line 9: @@
 === Piezo ===
-see: how to make a contact mike: using piezo disks to pick up tiny sounds
+see: how to make a contact mike: using piezo disks to pick up tiny sounds, chapters 7-8
 === contact-mic-circuit ===
@@ Line 25: / Line 25: @@
 <cite> {{tamiwiki:projects:collinshandmade_electronic_music.pdf|collinshandmade_electronic_music.pdf, chapter 23}}  </cite>
 </blockquote>
+==== more ====
+  * http://www.mo-seph.com/projects/piezocrystals
+  * https://www.zachpoff.com/resources/alex-rice-piezo-preamplifier/
+  * https://till.com/articles/PreampCable/
+<blockquote>
+{{:tamiwiki:projects:pasted:20231126-002227.png}}
+A piezo element can be thought of as a sound-dependent voltage source in series with a large capacitance of about 15nF. Here the trouble starts. You need to put this into a load which is higher than the impedance of the series capacitor at the lowest frequency of interest. If that is 20Hz, since the impedance of the capacitor is 1/2pifreq*C then you want that to be > 530k. I’ve terminated mine in 3.9M because that’s what I had to hand.
+<cite>http://www.richardmudhar.com/blog/using-piezo-contact-mics-right/</cite></blockquote>

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