In the picture below, the red arrows (current flow) are all pointing towards GND.
1. However, if you look at the input (=Ic gate) positionally, isn't it a parallel connection in the circuit?
2. If so, shouldn't it also flow in the direction of the blue arrow from VCC?
3. Also, even if the input impedance is high, a very small amount of current will flow and there is no voltage drop in the pull-up resistor, so the voltage of VCC will also be applied to the input..
Even if it seems to make sense if you simply accept it, if you try to dig a little deeper, it all gets twisted.. It's frustrating.
Additional responses from the respondent
The formula for the voltage division law is simple, and web searches work well, so I won't give you an answer.
I'll just explain the concept.
Let the switch contact resistance be 10 mohm.
10K and 10m are a million times different.
That is, it is equivalent to connecting a million 10m ohms in series between 5V and 0V.
Of course, if you measure the voltage of the one closest to 0V, it is of course almost 0V.
(Voltage divided by 5V divided by million if calculated using the Guji formula)
Additional questions from the questioner
Out of 3 answers...
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When the switch is pressed, the resistance ratio of the switch resistance (about a few m ohms) and the pull-up resistor (usually about 10K ohms)
The voltage across the input pin is close to 0V.
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Is it true that it is established according to the voltage division law? Is there a simple formula for a 5V power supply?
1. However, if you look at the input (=Ic gate) positionally, isn't it a parallel connection in the circuit?
-- can be viewed in parallel.
2. If so, shouldn't it also flow in the direction of the blue arrow from VCC?
--The switch contact resistance is very small and the input impedance is very large, so most of the current flows through the switch.
3. Also, even if the input impedance is high, a very small amount of current will flow and there is no voltage drop in the pull-up resistor, so the voltage of VCC will also be applied to the input..
--It is correct that the Vcc voltage is applied to the input when the switch is not pressed.
When the switch is pressed, the resistance ratio of the switch resistance (about a few m ohms) and the pull-up resistor (usually about 10K ohms)
--The voltage across the input pin is close to 0V.