On Sun, 15 May 2016 23:36:38 -0700, the renowned DaveC
wrote:

http://imgur.com/Trvs5mk

This is a beeper piezo in a Fluke 117 DMM which quite beeping. Scoped the
piezo’s pads and... nothing.

An inverter (from the CD4069) is connected across the piezo. Guess I don’t
understand anything about driving piezos.

Is this a standard practice?
Cheers.

If you put an inverter across the piezo you get double the supply
voltage drive - push-pull. Not uncommon. Typically you'd drive each
side with two paralleled inverters and use another inverter to invert
the input to one pair.

The piezo element looks something like a ceramic capacitor
electrically. A series capacitor is often used.



--sp


--
Best regards,
Spehro Pefhany
Amazon link for AoE 3rd Edition: http://tinyurl.com/ntrpwu8