On the schematics below, I try to understand what does IC1b or IC1d mean. Could you help me to understand it?

schematics of electronic dice

Image source: Making Easy Circuits - Electronic Dice Circuit

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    \$\begingroup\$ Nabla - Hi, Please note the site rule which requires that when a post includes content (e.g. text, image, photo etc.) copied or adapted from elsewhere, that content must be correctly referenced. As a minimum, for online material the source webpage or PDF etc. should be linked (see that rule regarding references for books / articles etc.). In order to help you, I found what I believe to be the source webpage link & added it. For the future, please remember it's your responsibility to do that :) Thanks. \$\endgroup\$
    – SamGibson
    Sep 14, 2023 at 0:22
  • \$\begingroup\$ Than you. I was in a hurry and forgot that part. \$\endgroup\$
    – Nabla
    Sep 14, 2023 at 12:43

1 Answer 1


IC1 (IS 74132) is a Quadruple 2-Input Positive-NAND Schmitt Triggers IC (for example: SN74LS132).

The four NAND gates are split into 4 separate symbols (IC1a, IC1b, IC1c, IC1d) for easier placement within the schematics.

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    \$\begingroup\$ I would say that the 74132 contains four NAND gates, rather than "is a 4 channel NAND gate". \$\endgroup\$ Sep 13, 2023 at 18:36
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    \$\begingroup\$ @PeterBennett some may argue this due to the differences between ANSI and IEC symbols. IEC can group each chip into one symbol block, whereas ANSI tends to split each logical unit into separate entities. Here is a paper, page 24, BS3939 (1991.) The shown schematic looks ANSI, but perhaps the O.P. has never seen gates drawn this way. One standard is perfect, and two is blasphemy. \$\endgroup\$
    – rdtsc
    Sep 13, 2023 at 19:03

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