A Discrete Transistor 7400 NAND GATE

If we did not have ICs then this is what a 7400 NAND gate would look like!

The 7400 TTL (and LS-TTL) quad NAND gate is one of the most common integrated circuits (IC) around. Here is a discrete transistor version. To show that it works it is used as an LED flasher. “

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