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Circuit Help


Mwee

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hi Mwee

i cant see the circuit u have posted properly here clearly.
the image is blurred....
yeah u can do with a smaller pot always but the only thing is the fear of getting damaged .because it will although divide the voltage but it wont offer much resistance between terminals 1 and 3.
thats it otherwise u may use an auto transformer.
good luck

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The schematic was a HUGE fuzzy JPG. I shrunk it and posted it as a clear PNG but had to start with the fuzz. It should look better on this page.

The 22M pot is backwards and if set to max, the bias current of the LM3914 across it would show a reading of half-scale or more without a signal. A 1M pot would work fine.

I removed a resistor that didn't do anything and added a very important supply bypass capacitor that all IC circuits need, especially if they use a battery.

The remaining resistor sets a fairly low LED current of only 5mA. A 560 ohm resistor would make the LEDs much brighter.

post-1706-14279142676876_thumb.png

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Hi Indulis,
I haven't seen an LED that performs as poorly as the Vishay TLLR5401 for many years.
The Fairchild MV8141 red LED that I use is 10 times brighter, has a wider viewing angle and can be 57 times brighter at its max continuous current. They are both diffused and the Fairchild LED costs only 5 cents more.

post-1706-14279142676966_thumb.png

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