building a 555 hysteretic oscillator

Thread Starter

hillshaveeyes57

Joined Sep 12, 2012
16
the schematics are right, but i'm not getting anything! yeah, this is my first project and i messed up a lot of times but the last few, i've gained a little more insight as to how it works and i'm still not getting my leds to flash OR even light up. i was thinking maybe i either wore out the protoboard (i used oversized hookup wire the first few times then downgraded to something smaller that fit into the slots better) or that my components are incorrect, or i fried something, even though i replaced the capacitor, pentometer, and 555 twice.

i'll try to post some pics of the project later.
 

help_mum

Joined Sep 13, 2012
6
the schematics are right, but i'm not getting anything! yeah, this is my first project and i messed up a lot of times but the last few, i've gained a little more insight as to how it works and i'm still not getting my leds to flash OR even light up. i was thinking maybe i either wore out the protoboard (i used oversized hookup wire the first few times then downgraded to something smaller that fit into the slots better) or that my components are incorrect, or i fried something, even though i replaced the capacitor, pentometer, and 555 twice.

i'll try to post some pics of the project later.
Why don't you get LTSPICE or one of the others and run your circuit on it then move to the Bread Board, Hase saved me hours of work and cost of parts.

H_M
Beginner
 

Thread Starter

hillshaveeyes57

Joined Sep 12, 2012
16
it fell out right before i took the pics and i just accidentally left it out.

the breadboard was kind of loose because the first hookup wire i used was a higher guage...almost too big for the slots.

think i should return the breadboard cause it might be FUBAR?
 

tracecom

Joined Apr 16, 2010
3,944
it fell out right before i took the pics and i just accidentally left it out.

the breadboard was kind of loose because the first hookup wire i used was a higher guage...almost too big for the slots.

think i should return the breadboard cause it might be FUBAR?
I don't know about returning it, but it's probably ruined. Even the wire in the pictures looks too big. I don't use wire bigger than 22 awg.

Just for reference, here's my version of the circuit you are trying to build. It works.
 

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Thread Starter

hillshaveeyes57

Joined Sep 12, 2012
16
i thought the wire was too large but was going to try to get away with it. that and i cheaped out and didn't buy a wire cutter and the ends were kind of crap when i was hooking it up. i'm returning it, getting some smaller guage and i'll give your design a try too. i know there's more than one way to skin it, but i'm still new at this whole thing. thanks so much for the feedback.
 

Wendy

Joined Mar 24, 2008
23,408
A side comment, the pictures are pretty accurate. The wires lay flat, the components are flush.

You will find in this hobby neatness is critical. It makes errors easy to spot, it prevents things like short. I have several kit boxes I put my project parts in, just because they are completely reusable.

I will rebuilt this project and take pictures, to show what I am talking about. Like I said, this project is verified, and is very repeatable. I went to a lot of effort to make it so. The pictures will be on file for future use, so they will be available for other use. I am a devote pack rat.
 

Audioguru

Joined Dec 20, 2007
11,248
Ho, ho, hee, hee.
Sorry but I always laugh when I see your messy tangle of wires that are much too long on a protoboard.

Of course the contacts are ruined.
 

Thread Starter

hillshaveeyes57

Joined Sep 12, 2012
16
the wire is 22 ga i think. fits into the holes fine, comes out fine. a csr at radioshack told me that it might just be having trouble making it through the circuit cause my wires are too thick. is that possible?

i hooked it up on fresh breadboard last night and did everything right and all i got was the two leds to light up. excuse my language but i'm really pissed. i don't think i've ever had this much trouble with anything. i'm just angry as hell about the pentometer not working. i've bought two tried both. the capacitor is fine.
 

Thread Starter

hillshaveeyes57

Joined Sep 12, 2012
16
yeah. i guess it is pretty funny. do you think too much wire could have something to do with the pentometer not registering?

dammit to hell i just want it to work already!!!!
 

tracecom

Joined Apr 16, 2010
3,944
the wire is 22 ga i think. fits into the holes fine, comes out fine. a csr at radioshack told me that it might just be having trouble making it through the circuit cause my wires are too thick. is that possible?
No. Don't forget that many of the CSR's at Radio Shack were at Shoe Carnival last week and will be at Pets R Us next week.
 

Audioguru

Joined Dec 20, 2007
11,248
Your wiring is too messy for us to see if THIS IS CONNECTED WRONGLY TO THAT.

The potentiometer is supposed to be a variable resistor. When it is 10k ohms then it charges and discharges the capacitor slowly so the LEDs blink back and forth slowly.
When it is zero ohms then the 10 ohm resistor charges and discharges the capacitor very quickly then both LEDs appear to be on all the time.
 

tracecom

Joined Apr 16, 2010
3,944
Your wiring is too messy for us to see if THIS IS CONNECTED WRONGLY TO THAT.

The potentiometer is supposed to be a variable resistor. When it is 10k ohms then it charges and discharges the capacitor slowly so the LEDs blink back and forth slowly.
When it is zero ohms then the 10 ohm resistor charges and discharges the capacitor very quickly then both LEDs appear to be on all the time.
AG may have hit on the problem. In order to use the potentiometer as a variable resistor, you can connect the wiper (middle terminal) to one of the other terminals (either one.) Then, use the two end terminals as shown in your circuit. See if that is the problem.
 
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