LED help

[Schwarzenyaeger]

I'm trying to build 8 LED VU meter made of IC-LM324 - Electronics Area
When I connect the power, the LEDs randomly flash but don't stay on. I can disconnect the circuit from the ground and the same thing happens.
Is this short circuiting?

I'm also doing this:
Two LED flashing alternate Display using LM324 | Eleccircuit.com
I'm getting constant light but it just won't flash.

 

[ecc83]

LED array: If you are using new components they are very unlikely to be faulty (actually unlikely even if 20years old!) so the problem will be "finger trouble" in other words, you have *****d up.
What form of construction did you use? If stripboard check for un cut tracks, tracks that should not have been cut. Get a glass on it and check for solder bridges. Check for components that have hopped into the wrong hole.
The circuit does not show an input coupling capacitor. Check the polarity of volts at the input and fit one as required. Check that the signal source does not have DC on it.

Another good diagnostic technique is "cold checks". That is, check resistances at points in the circuit from -ve volts and check that the readings agree with what you can deduce from the schematic.

Same goes for the LED flasher but TBQH I would have just built a two transistor flip flop!

N.B I came to a solderless breadboard very late in my electronics life (like 2 years ago and me 69) bloody handy things!

Oh! And I don't know where the guy that wrote " a VU meter is logarithmic" got that from cos it aini't!
The Peak Programme Meter IS approximately log' but little seen outside UK.

Dave.

 

[Schwarzenyaeger]

Im rebuilding the circuit as we speak
let's see

 

[mdainsd]

While you are rebuilding it put in some capacitors. One for each IC as close to the IC as is manageable. They can be from .01 to .1uF. They hook to the + and grnd pins of the ICs

 

[Schwarzenyaeger]

While you are rebuilding it put in some capacitors. One for each IC as close to the IC as is manageable. They can be from .01 to .1uF. They hook to the + and grnd pins of the ICs

Just put them between the + and grnd pin to the circuit?

I got the circuit to work btw. but using a different chip and slightly different design. Hmm...
I'm trying a simple compressor and octaver this weekend. I'll be back with results!

 

[Schwarzenyaeger]

We eventually managed to figure ou the faults.
Ended up building an octaver:

And the world's shittiest compressor:
No settings besides input level.

The next step would be to get them onto a PCB or something.