Easy way to do 350Hz Oscillator?

Question

First of all, if the place of my thread is wrong please guide me to correct one.

Greetings,dear internet people and fellow electronics hobbiysts.

Me and my friend work on a project which requires a 350Hz Oscillator in order to function properly.

However we could only "try" this on schematic and theoretically. The transistors we use have different hfe and this makes our job harder to obtain the theoretical circuit in real life.

My inquiry is that if any solutions on how to do this easier exists, please do inform me. I wonder if there is a crystal Oscillator way or maybe an IC? And please do consider the fact that I'm only a high school student who possesses little knowledge and who is new to electronics.

Thanks!

michaelkellett · Answer

Ok, this is your circuit simulated in LTSpice - where's the problem ?

It's called a phase shift oscillator and because this implementation has no sensible control of the feedback it will either not oscillate at all (R6 too high) or be distorted (R6 too low).

This circuit is very independent of transistor parameters.

if you need low distortion there are better circuits.

What are trying to do (ie give us the big picture, like "scare dogs" or "make a noise").

Is it a school project or task ?

MK

jw0752 · Answer

Hi Oguz,

Here is another option.

https://www.banggood.com/XR2206-Function-Signal-Generator-DIY-Kit-Sine-Triangle-Square-Output-1HZ-1MHZ-p-1206339.html?rmmds=search&cur_warehouse=USA

This kit is available for about $6.50 from China and will generate square, triangle, and sine waves from less than 1 cps up to 1 MHz. I set one up and ran 12 volts into it and I was able to generate 350 Hz at 5 V P-P. It was generally stable within two cps and .05 Volts. When you are done with your project you can use it as a simple signal generator. Here are some pictures of my test.

John

shabaz · Answer

Hi Oguz,

There isn't enough information about what quality you want, or accuracy either, so it makes it hard to recommend any particular option. However, maybe you might want to check out this blog post, which shows a 5Vp-p sine wave being generated by an Arduino:

Arduino: R-2R: Sine On You Crazy Diamond

jw0752 · Answer

Hi Oguz, I have a few questions for you. What type of wave output are you seeking, Sine, Square or other? How are you testing the frequency? How stable does the frequency have to be? Can you supply the schematic or drawing of the circuits that you have tried so far? This is a low audio frequency and should not be very hard to produce. If the stability is not too critical you should be able to use a resistive or capacitive trimmer to adjust the frequency once you have established a close approximation with fixed passives. There are many guys on the site that are real experts but I know they will be able to give you better suggestions if they understand better what your parameters and application are. John

dougw · Answer

Check this out - it explains how to pick components to get your frequency with a 555 chip: Nuts & Volts Magazine - For The Electronics Hobbyist

michaelkellett · Answer

Well in that case you should be OK with this circuit - it can't drive much of a load (certainly can't drive a loudspeaker) so you'll need a power amplifier, but it'll be fine for being a noise. MK

michaelkellett · Answer

Measure the DC voltages on the transistor base, emitter and collector and tell us about them - this circuit CAN work.

It's a really good exercise to work out in advance what you expect the voltages to be.

MK

Jan Cumps · Answer

alienozi wrote:

Thanks, John

We are trying to obtain a sine wave of 350 Hz at a Pk-Pk Voltage of 5V. Output must be continuous (or a good enough one).
I do have an oscilloscope, a Tektronix TDS 2002.
Here are the circuits we've worked on so far: (sorry for the quality of the pics and circuits )

Traditionally, the feedback+phaseshift network is drawn in front of the transistor.

Because it's a feed-back network, and by putting it in front of the amplifier, it shows that the signal is feeding back .

That's all.

alienozi · Answer

Thanks, John We are trying to obtain a sine wave of 350 Hz at a Pk-Pk Voltage of 5V. Output must be continuous (or a good enough one). I do have an oscilloscope, a Tektronix TDS 2002. Here are the circuits we've worked on so far: (sorry for the quality of the pics and circuits )