How to make Trigger voltage?

faraday

Member

• Dec 24, 2011

• #1

Hi all
I wanna to simulate a mono stable circuit with 555, but I don't know how to make Trigger voltage for 2 and 4 pins.
which voltage source should I use?

 

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faraday

Member

• Dec 24, 2011

• #2

Schmitt Trigger circuit with 555

hi all
again a 555 circuit
It's an Schmitt Trigger circuit, pin 7 has no connection and this causes error during simulation
What should I do with the pin?
(sorry for probable grammar mistakes.)

 

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crutschow

Well-Known Member

Most Helpful Member

• Dec 25, 2011

• #3

If pin 7 is not needed in the real circuit, you could just add a large resistor (such as 10meg) from pin 7 to ground for the simulation. That large value shouldn't have any significant effect on the circuit operation. (Make sure you use 10meg and not 10m which is 10 milliohms).

 

faraday

Member

• Dec 25, 2011

• #4

thank you so much.
and do you have any idea about How to make Trigger voltage in Orcad?
(that I said in the first topic.)

 

crutschow

Well-Known Member

Most Helpful Member

• Dec 25, 2011

• #5

Not familiar with Orcad but there should be a voltage source that you can configure to generate a pulse.