So I’ve decided to have a crack at 555 oscillator from a schematic that I’ve found somewhere. It seems to be connected up properly but it’s not oscillating. Like I said before I don’t have any speakers to connect so I’m using an LED instead but it’s not blinking. It’s just getting brighter when turning the potentiometer. Any suggestions chaps? I am new to this so talk to me like I’m 5.
I’ve tried every colour of LED I have. Also doubled the voltage and still no blinking.
I don’t have a 33kΩ resistor so that’s why I’ve got a bunch in series.
There is not much information on the breadboard image, what is the purpose of the circuit, what is the V value of the + ?
Be careful, some circuit found on the net simply does not work.
If you are looking to make an oscillator I might advise you to build an APC (Atari Punk Console), with two 555 (or one 556) and with a 9V battery.
But a speaker would be really necessary for all that, don’t you have an old headset, clock radio, car radio, … to recover a small speaker ?
Cranky correction: That’s not a schematic, it’s a layout. Schematics are usually much better organized to make clear what a circuit is doing. Layouts are a pain to analyze (and figure out if they make any sense or not, as @dud suggests there are many bad circuits on the web.).
With a 100k pot and a 10 nF cap the minimum frequency will be something like 160 Hz. That may be too fast to see the LED blinking. Persistence of vision and all that. If you have a larger cap you could try that for a lower frequency that might be easier to see.
But really, you need to hear what’s going on! In the US anyway (don’t know where you are) it’s yard sale season, finding a dirt cheap powered computer speaker or something like that shouldn’t be hard.
@Dud@analogoutput thanks for the advice guys! I only have 10k and 100k pots. But I think understand how a larger pot might do the job in that particular case. It was a 9V battery and then tried it again by doubling it up.
In terms of speakers, I never thought of using headphones! So I hooked up some iPhone headphones with a couple of crocodile clips to the simple oscillator and it worked! So we now have sound.
Think I might take your advice on the Atari punk console and give that a go. Seen some schematics that I can handle. But then again these are just ones I’ve found on a Google search, so they might not work. If you guys have a link to a good schematic that would be greatly appreciated, no worries if you don’t.
I’ll keep you guys posted with my progress. I have a goal in mind but I know I need to walk before I can run with this stuff so these little projects are a step in the right direction.
just found this and think it refers to what sam sams described as negative avalanche? by the way: i breadboarded it and tried two different transistors (cut their middle legs and stuff) but they seem to did not oscillate… (Nothing. Go Away. Stay Away!!) “More Oscillator fun! Zachary Vex have let us all know about very simple oscillator, but I just canīt recall what it was called. Got it! This is called negistor . Find more info here and here. Anyway, it uses only one transistor and the model is very important, you can only use 2n2222 there. Hereīs the schematic for that thing. If youīre picky (then you shouldnīt read this page!), you can use buffer after the output, so any low input impedance wont load the frequency down, because the 10uf output cap and the frequency determining cap are actually in parallel. Experiment with the pitch pot value and the freq.cap, until you get an oscillator that has nice range and will oscillate all the way through the pot travel.
And when you wanna go noise noise, dig this schematic , it uses two of these little crushers with one modulating the other. Use bigger freq.cap for the modulating oscillator so it has lower overall frequency(c1>c2). I havenīt tried, but you should have no problem chainging more of these, so all you get is total noise with no frequential consept. And you can also replace the mod osc with audio input, just keep the 10nf cap the same value. By the way, N.C. on the transistors base means īnot connectedī”
