Discussion in 'General Electronics Chat' started by R!f@@, Feb 11, 2012.
Would a 74HC series IC blow with 12V applied.
I say yes, cause one did at my face.
Didn't you check the specs? Vcc max is 7V.
I was going thru my junk and I happen to find an LCD with a couple of 7 seg digits. it has 74HC's all thru out. I just thought I could use the LCD in a project with numeric digits.
As I happen to have a 12V battery near by, I just jumped the supply cap...with some wires which also was near by..
The LCD lit to my surprise with 8's or 0's , I'm not sure and then bang ! . A shrapnel hit my face....so I searched and found it to 74HC393.
I had been coned..I always thought the HC series can handle more than 12V
The C series can handle more than 7v. The HC, HCT versions cannot.
Ah... the golden rule in electronics. NEVER EVER assume. The moment you assume. The probability of being wrong is 99.99%
But assumptions is what makes electronics design possible or easier.
And that is why the path of the designer is beset by dead circuits on all sides
I have had finger brands of parts manufacturers in mirror image, thought fortunately they healed over time. I have also destroyed protoboards (multiple), with great big melted spots where the parts used to be. I have turned capacitors into foil popcorn. I have left craters in chips where silicon used to be.
In other words, this is normal.
If it was a MOSFET....then it could have been normal
Blowing IC's is a first .
I believe the CD4000 and 74C00 series are the only CMOS logic families that can work at up to 15V.
Actually some of the CMOS family can to to 20V, especially the 4500 series.
Congratulations R!f@@. You are now the 10th member of the prestigious group who have posted 5K or more and fewer than 10K posts.
HUH !! Caramba...
I passed 5000.