User manual

8 Off at the push of a button

We will use a push-button switch instead of the alarm loop of

the last experiment. In the normal state, the switch is open.

But when you press the button, the contact will close, and

this will turn off the red LED.

The NOT circuit

Isn’t it strange, we are closing a contact and switch on current,

but by that another current is switched off. Switching on caus-

es switching off, that is the exact opposite. However, this is

another essential basic circuit in computer technology and it is

called a NOT circuit. The other term for this is „Inverter“. Like

the AND circuit, the NOT circuit is a basic logic circuit. You can

build an entire computer from a lot of AND NOT circuits.