Hardware Hacking - Nicolas Collins

Hardware Hacking 75

Chapter 20: More Oscillators

You will need:

• A breadboard.


• 1 CMOS Quad NAND Gate Schmitt Trigger Integrated Circuit (#4093)


• Assorted resistors, capacitors, pots & photocells.


• Some solid hookup wire.


• A jack to match your amp.


• A 9 volt battery and connector.


• An amplifier.


• Hand tools.

Here are some variations on our basic oscillator design.

Gated Oscillator

The Schmitt Trigger circuit that turns each Inverter in the 74C14 into a potential
oscillator is also found in other CMOS digital circuits. Most useful is the 4093
“Quad NAND Gate.”

+ 9 volts

ground

4093

This chip consist of 4 identical NAND gates. Note that this chip has the same
power connections as the 74C14 Hex Inverter chip we used in the previous two
chapters: + voltage to pin 14, ground to pin 7. There are two NAND gates on
each side of the chip, but unlike the 74C14, there is mirror symmetry on each
side: the outputs of each gate face each other, rather than the same direction.

A NAND gate is a variant of the basic binary function of an AND gate, which for
two inputs generates the following outputs: