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Fairchild Semiconductor 4060BCN 14 Stage Ripple-Carry Binary Counter

7/16/07 While the rain keeps me from airbrushing, I've been playing around with these nifty chips that I just learned about. Everyone likes looking at a model, but what really wows a crowd are lights. Of course, static lights get boring, so I've been investigating an easy solution to flash multiple LEDs.

Enter the Fairchild Semiconductor 4060BCN chip. These sweet babies pulse current between 10 of their pins. They operate anywhere between 3-15 Volts and depending on the voltage provided, can pulse quite a few LEDs with varying timings, strobes and slowly changing patterns. They're cheap at about 65 cents apiece from digikey

Binary counter chips use a frequency established by a resistor/capacitor combination. This frequency is called the 'clock'.

On a 14-stage counter, 10 of the pins are numbered Q4-Q14, and those pins pulse with a timing set by the clock divided by 2 to the power of the Q number. (see the diagram).

The end result is that each pin pulses at a different rate. Depending on the input voltage, you can drive multiple LEDs off of each pin.

The 4060 chip will only draw 11mA of current for itself, and pass the rest of the current from the voltage source to the pins. The specification for the chip states that the minimum current is 8mA per pin, but the spec didn't list a maximum current.

I'm overdriving the pins with ~11mA. This may or may not shorten the life of the chip, but I'm not worried about it. Most LEDs require 20mA of current, so these are slightly dimmer at 11mA, but still quite bright. Since I have 9V here, I could drive 6 LEDs on a single pin. I still haven't figured out the maximum number of LEDs the chip can handle altogether, but I've had 15 blinking happily away quite brightly from this same 9V battery.

I ran these LEDs with no limiting resistors right from the chip for a couple of days and they didn't heat up at all. I used a 12V wall wart instead of the 9V battery, so each pin was supplying in excess of 100mA. This will shorten the life of the LEDs (as they overpowered by 5x the spec), but they didn't heat up or burn out yet, and this is just an experiment, after all.

9V batteries contain about 500 mA-hours of life, so drawing 55 mA with 4 LEDs along with the chip at ~11 mA, the battery should last around 9 hours of continuous operation

 
MMVII Guy Garrison - All rights reserved. Use without authorization is prohibited.