TTL astable multivibrator
Électronique / Electronic
7400

Even multivibrator circuits can be made from NAND gates. This Project is an example of an astable multivibrator - can you guess what that means?

Make a guess, and then build this Project to find out. Put power ON after you finish making all the wiring connections. You'll see LED 1 flashing on and off.

This is like the operation of many of the multivibrators we've used in earlier circuits, A stable means the multivibrator keeps switching back and forth, between 0 and 1.

As you remember, that's what most of the multivibrators you've built so far do. You shouldn't have much, trouble figuring out how this particular circuit works and yes, those two 100 uF capacitors make it all possible.

Try using the other electrolytic capacitors in place of the 100 uF values and see what effect they have on LED 1 (be sure to observe correct polarity).

If you want to see the output of this circuit in a different way, try adding the Meter and Control in place of LED 1, it can be done, but we'll let you figure out how.

By now you can see why NAND gate ICs are so popular. The 7400 Quad 2-input NAND IC is one of the most widely used electronic components in the world, mainly because it can be used in so many different ways (and you can probably think of many more).