Experiment 5 - The THRESHOLD Input
How do you connect the NE555?
Find out how you reset the state of the output with the
From the internal circuit diagram of the NE555 you can see
that the THRESHOLD input
Pin 6 (THR)
is connected to a comparator.
The second input of the comparator
is connected to the voltage divider,
at which the voltage
V = 2/3
= 6 V
The output of the comparator is connected
to the RESET input of the RS latch.
Internal circuit diagram THRESHOLD input NE555.
Now consider the circuit shown...
Circuit THRESHOLD input NE555.
Circuit diagram THRESHOLD input NE555.
As soon as you push the pushbutton switch S2...
At the THR
input a voltage of
Vcc is applied,
which is greater than
V = 2/3
= 6 V ,
therefore the output of the comparator
goes to HIGH
thus the RS latch gets a
RESET and resets the latch,
and the output OUT goes to
LED1 goes back on.
But there is also another way to reset the NE555...