Christmas Display

Thread Starter

k7elp60

Joined Nov 4, 2008
555
I was looking thru may parts to make a Christmas display with the maximum number of LED's and minimum # of parts. The attached circuit uses three quad 2 input nand schmitt triggers(CD4093) and one 1 of 8 switch (CD4051). The neat part is it only uses one external resistor as current limiting resistor for 8 to 24 LED's. If a 9v battery is used and the Vf of the LED's totals near 8V then no resistor is needed as the internal 100 resistance of the CD4051 does the current limiting.
Caution the maximum LED current should not exceed 25mA.
Ned
 

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sheldons

Joined Oct 26, 2011
613
not very economical use of your 4093 gates here...you only need one gate ,one cap and one resistor and you have an osc....so you could use one 4093 with one unused gate spare but its quite an interesting way to use that ic
 

Thread Starter

k7elp60

Joined Nov 4, 2008
555
Yes you are so right. I get to eliminate one of the CD4093's.
Thanks for you input sheldons. I'll redraw the schematic.
 
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