Hello All
I am a novice at this and I just built a door alarm using a kit. This is the kit schematic:



I built it and it works fine, but I want to analyze the circuit using sim software (Yenka). So this is the sim version I did:


When I close the first switch (S1) in the sim above the alarm sounds but IC1d and IC1a blow up (they are pins on an IC4093). The error I get is:


I don't know what I am missing here. I have checked the circuit and cannot see the problem. The only odd thing is that the kit schematic requires a BC328 PNP transistor shown as Q1. The sim software doesn't have a BC328 transistor so I selected a BC178 and changed the ratings to match what I think mimics the BC328:



So could this be the problem, being that the sim software does not have the required transistor. Or, if the ratings I used on the BC178 actually do the same as a BC328 then I am completely lost as to why IC1d and IC1a blow up.

If it is the transistor these are the only choices the sim software provides for PNP transistors:



They seem to be a limited set of choices but I assume you can modify the ratings to get the desired transistor, but I am only guessing.

Any help appreciated. Is it how I have setup the transistor, or is there another problem in the sim circuit?

 

Hello,

How did you define the supply voltage of the 4093?
(are the supply connections made).
Better use the ztx1151a for the bc328. it matches the specs better.

Bertus

 

You need to add a supply pin for 4000 family.

 

Hello,

How did you define the supply voltage of the 4093?
(are the supply connections made).
Better use the ztx1151a for the bc328. it matches the specs better.

Bertus

No idea how Yenka works. My question: how is Vcc defined?

 

Hi Bertus, still blows up with a ztx1151a.

The sim does not let me set the supply voltage so I assume that the circuit so supposed bring it down to 1 V.

I did also note that on IC1c pins 14 and 7 are meant to go to ground but the sim tool does not give me access to pin 14 and 7 so I assume this is done automatically by the sim?

 

Hello,

Did you see the post of Jony130?
He shows a picture how to set the voltage:

Bertus

 

So, no chances of having two or more different PSUs?

 

Thanks Bertus, Jony130 and atferrari, Its working now, as shown below

I can't believe it, thanks Jony130, you really helped with that image showing Vdd.

I also used the ztx1151a as you suggested Bertus and had to up the reverse B/E voltage to 12v otherwise the transistor would blow up.

Thanks everyone, amazing.

Now could someone explain what Vdd does and why it is needed, is it a physical component. I did not see a Vdd on the actual hardware. Whats the story here? I thought the whole circuit gets its power from the 12 volt supply??

 

Hello,

What happens when you move the VDD point atfter the switch S1?
Now the reverse voltage can be indeed 12 Volts, as the 4093 has voltage and the transistor not.

Bertus

 

The error I get is

the simulator assumed the digital components are powered at 5v, vs. 12v rail.

You can lower the 12v rail and if the error goes away, that's it.

 

Agree.

In proteus TTL Vcc is 5V standard. But CMOS defaults to 5V too, but it can be changed to 10V or 15V optionally by clicking on the gate.

Allen

 

the simulator assumed the digital components are powered at 5v, vs. 12v rail.

You can lower the 12v rail and if the error goes away, that's it.

Hi dannyf, would you mind elaborating. Do you mean lower the voltage with a resistor just before the 4093?