Experiment 6 - The RESET Input

How do you connect the NE555? Find out how you reset the state of the output with the RESET input.

From the internal circuit diagram of the NE555 you can see that the RESET input, Pin 4, is connected directly with the RS latch. Now you have the opportunity to reset the NE555.

     

Internal circuit diagram RESET input NE555.

Now consider the circuit shown...

Circuit RESET input NE555. (Enlarge)

Circuit diagram RESET input NE555.

As soon as you push the pushbutton switch S3...

• At the RESET input a voltage of 0 V applies,
• thus the latch is forcefully reset,
• and the output OUT is pulled down to LOW. LED1 goes on.

As long as you keep S3 pressed, OUT stays on LOW. You will take advantage of this in later experiments.

In the next step you get to know the final output...