Building a simple oscillator

[theyreinthehouse]

Hi, hopefully this is the right place to post this question. I’m looking to build an oscillator. I have all the parts ready to order and I wanted to double check that I’m not making an obvious mistake. I’m completely new to this and I thought it would be worth a second opinion to know if the parts I found are correct based on the guide I’m following, if anyone has the time to take a look. Any pointers are appreciated.

Here’s a list of the parts based on the guide that I’m following:

1x 1k resistor,
1x 100k resistor,
1x 10k 16mm potentiometer,
1x 2N3904 transistor,
1x LED,
1X 10μF capacitor

And here’s the list of these parts that I’ve found and plan to order:

1K TruOhm 0.25 Watt Resistor - Irish Electronics.ie

irishelectronics.ie

1/2W Metal Film Resistor 15k Ohm -100k Ohm - Irish Electronics.ie

irishelectronics.ie

10K 16mm Linear Potentiometer - Irish Electronics.ie

irishelectronics.ie

2N3904 Audio Transistor NPN - Irish Electronics.ie

irishelectronics.ie

WHITE LED 5mm WATER-CLEAR - Irish Electronics.ie

irishelectronics.ie

TANTAL CAPACITOR 10µF / 16V - Irish Electronics.ie

irishelectronics.ie

I’m planning to solder it on this strip board - https://irishelectronics.ie/epages/...ath=/Shops/950018241/Products/2439&Locale=en_ IE

Here’s an illustration of the schematic from the video that I’m following -

https://imgur.com/a/g1b0pOi

 

[crutschow]

Since that transistor has 3 connections and the schematic only shows two connections, I don't see how it can work(?).

 

[theyreinthehouse]

Since that transistor has 3 connections and the schematic only shows two connections, I don't see how it can work(?).

That was actually covered in the video. He said to just cut off the middle leg of the transistor.

 

[rjenkinsgb]

That is definitely not a circuit I'd recommend, it is relying on the transistor "breaking down" due to reverse connections & overvoltage, rather than being any conventional kind of oscillator.

There are many others that are more reliable and more predictable!

 

[Papabravo]

That was actually covered in the video. He said to just cut off the middle leg of the transistor.

Ummm...simple oscillator might be an oxymoron. Cutting off the middle leg of a transistor is akin to the maker of the video pulling YOURS! If you find it on the internet -- it must be true! Right? -- Why would they ever lie to you. Sorry about the money you've wasted.

 

[danadak]

Post a link to video.....

Hard to imagine this working as breakdown of 2N3904 >> your supply V.

Unless circuit is depending on internal parasitic and junction C to create a turn on
and discharge cap until transistor turns off. Hard to see how this is stable, worthwhile,
or usable, let alone frequency predictable. Maybe build a Theremin out of it with
a tin plate connected to base.....if it oscillates


Regards, Dana.

 

[theyreinthehouse]

Ummm...simple oscillator might be an oxymoron. Cutting off the middle leg of a transistor is akin to the maker of the video pulling YOURS! If you find it on the internet -- it must be true! Right? -- Why would they ever lie to you. Sorry about the money you've wasted.

Lol calm down. I just asked for help because I have no clue what I’m doing. I didn’t spend any money. I thought it would prudent to ask what people with knowledge thought first. Thanks for the reply

 

[theyreinthehouse]

Post a link to video.....

Hard to imagine this working as breakdown of 2N3904 >> your supply V.

Unless circuit is depending on internal parasitic and junction C to create a turn on
and discharge cap until transistor turns off. Hard to see how this is stable, worthwhile,
or usable, let alone frequency predictable. Maybe build a Theremin out of it with
a tin plate connected to base.....if it oscillates


Regards, Dana.

Thanks for the informative reply. I appreciate it. Here’s a link to the video:

If it’s not obvious by now, I don’t think I can overstate how little I know about this. I’m trying to find my way to learning about this kind of thing and decided to start here because I love learning about sound.

 

[theyreinthehouse]

That is definitely not a circuit I'd recommend, it is relying on the transistor "breaking down" due to reverse connections & overvoltage, rather than being any conventional kind of oscillator.

There are many others that are more reliable and more predictable!

Thanks, I really appreciate the input. I understand that you would not recommend using this circuit but can I ask whether the parts I’ve shown that I sourced online are actually the same as those on the list I found on the original guide for this circuit? I’m not planning on going ahead with this if it’s not a good way to do it but I’m just curious as to whether I actually managed to find the right parts for the circuit as shown.

 

[danadak]

Do you want the osc to be of use or this is just an investigation ?

If of use what do you have in mind for its use ?

A simpler osc -

But takes a higher V to run it. A low V using simple logic gate -

Some oscillators here, post #6, 555 timer -

https://www.edaboard.com/threads/blinking-led.403933/#post-1740173



Regards, Dana.

 

[Papabravo]

Lol calm down. I just asked for help because I have no clue what I’m doing. I didn’t spend any money. I thought it would prudent to ask what people with knowledge thought first. Thanks for the reply

I don't fault you for being taken in at all. I fault people making bogus videos for the sake of grabbing a bit of attention and for wasting peoples time and energy. Learning things is a laudable endeavor and you should continue with that enterprise but try to be a bit more skeptical until you are able discern the wheat from the chaff.

 

[theyreinthehouse]

I

Do you want the osc to be of use or this is just an investigation ?

If of use what do you have in mind for its use ?

A simpler osc -

View attachment 139301

But takes a higher V to run it. A low V using simple logic gate -

View attachment 139302

Some oscillators here, post #6, 555 timer -

https://www.edaboard.com/threads/blinking-led.403933/#post-1740173



Regards, Dana.

I guess a bit of both. It’s an investigation in the sense that I want to make it in order to try and understand how it actually works. On the flip side, it would be of use to me to have several of them that could be tuned together, as I’ve seen done. Thanks for the useful feedback. I’ll absolutely look into that. I appreciate you taking the time to help me.

 

[theyreinthehouse]

I don't fault you for being taken in at all. I fault people making bogus videos for the sake of grabbing a bit of attention for wasting peoples time and energy. Learning things is a laudable endeavor and you should continue with that enterprise but try to be a bit more skeptical until you are able discern the wheat from the chaff.

Well thanks. I can sleep better now I know you don’t fault me. I of course wasn’t being overly skeptical or otherwise when I saw this tutorial. Mainly because it would seem a bit bizarre to me that a channel, which at the time of this video being posted the channel had 14k subs and now five years later it has half a million subs, would blatantly set about making a circuit that not only doesn’t work but also to show it working, make follow up videos concerning the same topic, and then to also actually point out in his own video that he hadn’t realised that the third transistor leg needed to be snipped off to make it work. Why not just not include that if the video is somehow a lie?

I mean, you can say you laud my endeavours but honestly, your replies come across as a little bit patronising telling me I’ve been taken in, sorry about the money you wasted and sImPLe oScILlaToR mIgHt bE aN oXyMoRon. Like how is that helpful? Luckily I did actually get an extremely informative reply in a thread on Reddit where not only was I told by the commenter that he had made this exact oscillator exactly as described, and that it worked, but also pointed me in the direction of more pragmatic versions of it, similar to some of the commenters on here. Like it’s fair enough if this isn’t the best way of going about making the thing but I don’t see you offering any assistance. The implication of your reply is that the video I’m following was actually faked. Like I’m totally new to this and I reached out for help and am met with “be more skeptical”…? Try reading back your own sentences before you post them.

 

[rjenkinsgb]

Hard to imagine this working as breakdown of 2N3904

Without trying it, I'm guessing that emitter and collector are reversed, so it's the VBE breakdown providing base current and it then turns hard on, until the cap discharges.

 

[danadak]

On the flip side, it would be of use to me to have several of them that could be tuned together, as I’ve seen done.

If you can describe the larger design / goals that might want a different solution.

Questions like waveforms desired, freq range, stability, tracking accuracy / synchronization
why needed, control method (pot, voltage, current, Temperature....)....

Just a thought.


Regards, Dana.

 

[Papabravo]

Well thanks. I can sleep better now I know you don’t fault me. I of course wasn’t being overly skeptical or otherwise when I saw this tutorial. Mainly because it would seem a bit bizarre to me that a channel, which at the time of this video being posted the channel had 14k subs and now five years later it has half a million subs, would blatantly set about making a circuit that not only doesn’t work but also to show it working, make follow up videos concerning the same topic, and then to also actually point out in his own video that he hadn’t realised that the third transistor leg needed to be snipped off to make it work. Why not just not include that if the video is somehow a lie?

I mean, you can say you laud my endeavours but honestly, your replies come across as a little bit patronising telling me I’ve been taken in, sorry about the money you wasted and sImPLe oScILlaToR mIgHt bE aN oXyMoRon. Like how is that helpful? Luckily I did actually get an extremely informative reply in a thread on Reddit where not only was I told by the commenter that he had made this exact oscillator exactly as described, and that it worked, but also pointed me in the direction of more pragmatic versions of it, similar to some of the commenters on here. Like it’s fair enough if this isn’t the best way of going about making the thing but I don’t see you offering any assistance. The implication of your reply is that the video I’m following was actually faked. Like I’m totally new to this and I reached out for help and am met with “be more skeptical”…? Try reading back your own sentences before you post them.

Well, I guess you must be quite capable of helping yourself then.

 

[AnalogKid]

I fault people making bogus videos

If you are referring to the video in post #8 - what is bogus about it? On other forums this is a well known circuit, posted by Dick Cappels, the guy who (I think) invented it.

Here is a link to the circuit (not by the original author):

How to Build a Relaxation Oscillator with a Transistor

In this project, we show how to build a relaxation oscillator with a single transistor.

www.learningaboutelectronics.com

ak

 

[theyreinthehouse]

Well, I guess you must be quite capable of helping yourself then.

Nope. That’s actually not what I said. This is a subject about which I have zero knowledge but I am trying to learn, which is why I asked for help here and elsewhere. I’m not sure of what part of that you didn’t understand but based on the other replies that I’ve now seen, you apparently didn’t even correctly understand the initial concept itself.

 

[theyreinthehouse]

If you can describe the larger design / goals that might want a different solution.

Questions like waveforms desired, freq range, stability, tracking accuracy / synchronization
why needed, control method (pot, voltage, current, Temperature....)....

Just a thought.


Regards, Dana.

Thank you. Tbh, I might have been overreaching in mentioning creating many of these that can be tuned together. I’m still in the early stages of getting stuff together to build just this first circuit and trying to understand it.

To make this clear, I’m effectively just copying what I’m seeing someone doing on a video to see if it will work and then reverse engineering what I have in order to better understand each component, if that makes sense. I really only made this thread not to scrutinise the actual schematics - I assumed them to be of sound design just based on the video showing the thing actually working and the hundreds of comments not suggesting otherwise - but to just check whether the parts I had sourced were actually the right ones according to the list and schematics.

But I really do appreciate all of the input I have received and it’s absolutely given me plenty to research but unfortunately I just don’t have much to give back by way of explaining my design or goals beyond this because, as I said in an earlier reply, I essentially have no knowledge of anything about circuits.

 

[Papabravo]

If you are referring to the video in post #8 - what is bogus about it? On other forums this is a well known circuit, posted by Dick Cappels, the guy who (I think) invented it.

Here is a link to the circuit (not by the original author):

How to Build a Relaxation Oscillator with a Transistor

In this project, we show how to build a relaxation oscillator with a single transistor.

www.learningaboutelectronics.com

ak

My post was made before post #8. Your inference makes no sense unless time travel does.