Crystal oscillator  - Page 1
Forum section: electronics / beginners

author: glinjik
author_rank: Regular Contributor
timestamp: December 26, 2020, 11:09:34 am
content: hi does anyone have a circuit that can control a piezo buzzer frequency using a crystal ? im looking at a 8mhz crystal

author: MIS42N
author_rank: Frequent Contributor
timestamp: December 26, 2020, 11:22:46 am
content: I don't think there's enough information to offer help. What sort of control? and why use a crystal?Some Arduino nano boards have an 8mhz crystal, program the uP to do what you want.https://www.banggood.com/3_3V-8MHz-ATmega328P-AU-Pro-Mini-Microcontroller-With-Pins-Development-Board-Geekcreit-for-Arduino-products-that-work-with-official-Arduino-boards-p-916211.htmlhttps://create.arduino.cc/projecthub/SURYATEJA/use-a-buzzer-module-piezo-speaker-using-arduino-uno-89df45

author: glinjik
author_rank: Regular Contributor
timestamp: December 26, 2020, 11:26:56 am
content: just to make it buzz at any frequency using a crystal rather than transistor circuit

author: Ian.M
author_rank: Super Contributor
timestamp: December 26, 2020, 02:33:40 pm
content: Quote from: glinjik on December 26, 2020, 11:26:56 amNope. An 8MHz (or any other) quartz crystal doesn't provide amplification, so cant oscillate on its own, and its impractical to make it oscillate, and divide that frequency down to the audio range without using transistors or ICs comprised of transitors.OTOH tube Pierce (crystal) oscillators are practical, although a ten stage binary divider chain of tube Eccles Jordan bistables, the first toggling at 8MHz, to get it down to 7.812KHz to drive the piezo would be a large, ugly and power-hungry method of achieving the desired aim.If frequency stability of the audio isn't a priority, *TWO* 8MHz crystal oscillators could be pulled in opposite directions and mixed to get a beat frequecy in the audio range, reducing the circuit to three tubes. You wouldn't want to use a single tube triple triode, as it would be very difficult to prevent the oscillators injection locking to each other resulting in loss of output frequency if they weren't individually well screened with very well filtered power.

author: Doctorandus_P
author_rank: Super Contributor
timestamp: December 29, 2020, 02:05:51 am
content: Sure there is.Just use your 8MHz crystal to any small microcontroller and write some software to output some melodies.You don't even need no crystal, as mos microcontrollers have a built-in RC oscillator.

author: Ian.M
author_rank: Super Contributor
timestamp: December 29, 2020, 02:20:18 am
content: Quote from: Doctorandus_P on December 29, 2020, 02:05:51 amName me any IC with a built-in Pierce oscillator made on a process that doesn't use MOSFETs or BJTs!Quote from: glinjik on December 26, 2020, 11:26:56 amIts still *technically* a transistor circuit even though its in an IC. If glinjik wants to relax the constraint to "just to make it buzz at any frequency using a crystal rather than adiscretetransistor circuit" then yes, your suggestion would do the job, as would a74HC4060oscillator + 14 stage binary divider chain chip. ACD4060would probably work at over 12V, but its too slow at low supply voltages for an 8MHz crystal to work.

author: bob91343
author_rank: Super Contributor
timestamp: December 29, 2020, 02:53:56 am
content: He didn't mention an 8 MHz crystal. He said it was 8 mHz. That is a very low frequency.You want precise answers, ask precise questions.

author: Ian.M
author_rank: Super Contributor
timestamp: December 29, 2020, 03:02:42 am
content: OUCH! I'm justly flamedQuote from: bob91343 on December 29, 2020, 02:53:56 amHere's the somewhat pissy response I wrote back in 2017 to someone who wanted to use a 12mhz crystal with a PIC18F14K50:https://www.microchip.com/forums/FindPost/993660Please continue flogging the proper S.I. prefixes horse!

author: bob91343
author_rank: Super Contributor
timestamp: December 29, 2020, 07:38:50 pm
content: Case is important. A former associate suggested that if a unit is named after a person, it should be capitalized. Such as Volts, Amperes, Ohms, Hertz, Henries, Farads. He also suggested to do that even if not the initial letter, such as MHz or kOhms, mV, etc. A major case of abuse of these pseudo-rules is deciBels. Should be dB not db. Named after A. G. Bell.Strictly speaking even a word in the previous paragraph should be written et c. because it's an abbreviation of one word of a two-word expression, et cetera.It's another case of people being unwilling to think. I guess it's too much work. Not to speak of all the work I went through to write all of this.Apologies if it's too far off topic.

author: ejeffrey
author_rank: Super Contributor
timestamp: December 29, 2020, 11:12:49 pm
content: Quote from: bob91343 on December 29, 2020, 07:38:50 pmYour associate is wrong or your interpretation of their rule is wrong.According to every standard and style guide I have ever seen volts, amperes, hertz should *NOT* be capitalized in English when used to refer to physical units unless they would otherwise be capitalized such as at the start of a sentence or in a title. They should of course be capitalized when referring to the people in question. It's not a pseudo rule it is a real rule.Abbreviations for units named after a person such as V, A, \Omega, J should be capitalized including when preceded by a prefix such as mW or hPa but units not named for people do not get this treatment: m, kg, s, ml (although ml is not an SI unit)Decibel should indeed be abbreviated dB and almost always is, certainly in formal writing but deciBel would be incorrect.