LTspice switch not working

K

kingofjong

Member

• Jul 30, 2018

• #1

Hi

I am using an spst switch from yahoo group in my adc file and the switch is not working properly. I have set the switch to 0 witch means of, but voltage is still going through. I have tested the switch in the simple_switch file and 0 gives you 0 volts. Not sure what I am doing wrong in adc file. The picture bellow will provide more information. The highlighted parts are where I probed the circuit. I would appreciate any help.



Thanks

 

crutschow

Well-Known Member

Most Helpful Member

• Jul 30, 2018

• #2

You schematic for the adc simulation is too small to see the details.

If you want the voltage to go to zero, you need to add a resistor (say 10kΩ) going to ground.
An open circuit from the relay output is an undefined state.

 

Last edited: Jul 30, 2018

Inquisitive

Super Moderator

• Jul 30, 2018

• #3

Attach your raw files .asc so members can help.

 

K

kingofjong

Member

• Jul 31, 2018

• #4

Hi

I have attached my .asc file. I appreciate all the help.

Thanks

 

Attachments

• adctest.asc

  1.2 KB · Views: 90

Last edited: Jul 31, 2018

alec_t

Well-Known Member

Most Helpful Member

• Jul 31, 2018

• #5

Wrong .asc file?

 

K

kingofjong

Member

• Jul 31, 2018

• #6

Hi

Nope this is the correct .asc file. I changed the file in the picture to test some stuff out. I thought I could solve the problem. But I am still getting the same results in the file I posted. In the new file I probed the output of the wire with the resistor to get voltage.

Thanks

 

Last edited: Jul 31, 2018

alec_t

Well-Known Member

Most Helpful Member

• Aug 1, 2018

• #7

Connect a 10k (not critical) resistor between the CLR inputs and ground, as Crutschow suggested: otherwise leakage current through the switch keeps the CLR inputs high.

 

crutschow

Well-Known Member

Most Helpful Member

• Aug 1, 2018

• #8

If you don't follow the suggestions we make, then it's difficult to solve your problem.

 

K

kingofjong

Member

• Aug 2, 2018

• #9

Thanks that solved the problem