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My Leds are really dim. How Can I make them brighter?

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Cyclone

New Member
Hi


I am making a mod for my computer, which uses 10 leds with a Decade counter, which is controlled by my remote.

I am using the 12volt supply with a 9v voltage regulator to power my mod. I am using the proper resistors for all 10 leds using the specs from the data sheets. So that parts fine. But the leds are really dim. So I disconnected the Decade counter and tried powering one of the leds directly to the power source with the proper resistor. It was twice as bright. Is The Decade counter drawing too much current?


Anyone know how I can make my leds brighter?
thanks.
 

Sebi

Active Member
Decrease the serial resistor for desired brightness.The counter output voltage always lower as supply voltage.If You drive the LEDs with multipplex-method, this also drastically decrease the brightness. Some CMOS IC-s have output current limiter about 6mA, in this case need transistors for each LED.
 
Use high side drivers, like ULN2003 or a transistor, or use buffers, be sure that the buffers output are TTL and check if your current is about 20 mA.
 

spuffock

Member
Buy some high brightness leds and replace them all. You wont run into problems with inadequate power supply this way .
 

laroche73

New Member
dim LEDs

What are you using for the decade counter? A 4017? Many logic families can sink more current than they can source, so you're better off driving the LEDs in a common-anode configuration (sinking current) rather than common-cathode (sourcing current). That requires an inverter for each 4017 output, so it may be simpler to use Spuffock's idea. The low current/high-efficiency LEDs work well on as little as 2mA, vs. 20 mA for standard LEDs.
 

Cyclone

New Member
Thanks for the replies. I tried the transistor idea and it raised the current 3x. Now my leds are as bright as they should be. :)
 
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