Rise And Fall Detector

Thread Starter

maker_2023

Joined Nov 20, 2023
167
Hello:

I am trying to simulate a rising edge and falling edge detector using a CD4093 NAND gate
with Schmitt trigger inputs. I get the following message wrt the gate.

U1:eek:ut:b1"Unknown circuit node:"vdd" requested in behavioral source.

Can someone please tell me how to fix this?

Thanks
 

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crutschow

Joined Mar 14, 2008
34,403
U1:eek:ut:b1"Unknown circuit node:"vdd" requested in behavioral source.
You are apparently using the CMOS model library (.lib cd4000_V.lib) that needs a positive voltage source with its output node labeled "Vdd" (no quotes) to provide its power, so change the label +5V to Vdd.
Vdd can be any value from 3V to 15V, and the CMOS input logic and output voltage levels will correspond to that.
 
Last edited:

ericgibbs

Joined Jan 29, 2010
18,835
hi m,
Try what @crutschow suggested.
E

There are a number of different versions of the CD4000 lib, the suffix v version needs the VDD that was noted.
E
EG57_ 1423.png
 
Last edited:

ericgibbs

Joined Jan 29, 2010
18,835
hi m,
Look in your LTSpice folder, it should be in Documents, find the lib folder, look and see which CD4000.libs you have in the folder.
E
 
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