XNOR circuit - Can any one build XNOR circuit

[danadak]

Regards, Dana.

 

[crutschow]

Dana.

The circuits in post #41 are XOR not XNOR.
Their main disadvantage is they they waste more than more than normal lamp current when one one input is on, and more than twice the lamp current when both inputs are on.

 

[danadak]

The point of the post, which I should have stated, was simplicity of
logic w/o active components. And yes they are not a low power design.

And XNOR switch in one leg the R and switch.

Regards, Dana.

 

[crutschow]

The point of the post, which I should have stated, was simplicity of
logic w/o active components. And yes they are not a low power design.

Okay.
It would appear that the bottom two circuits are the same except one uses four discrete diodes and the other uses a four-diode bridge.

So you don't consider diodes to be an active component?

 

[Buk]

I'm using a PNP to drive the LED, not an NPN.

Hm. You're using PNPs (2N3906) for ALL 3 transistors. Which I recognised, and tried, and decided must be a mistake as that was even less 'working' than with NPNs:

Of course, if you'd shared your LTSpice implementation, I wouldn't have had to try recreate it myself.

 

[Buk]

Hey sxy, if you find all this as confusing and unhelpful as I do, let's continue via PM and let the one-uppers play amongst themselves.

 

[crutschow]

must be a mistake as that was even less 'working' than with NPNs:

Not surprising it doesn't work since you have Q1 and Q2 backwards.

if you'd shared your LTSpice implementation, I wouldn't have had to try recreate it myself.

Since you were using Falstad, I didn't think you had LTspice.
Below is the LTspice file.

 

[Buk]

Circuit: * C:\Users\ms20b\Documents\XOR XNOR 3-Transistor.asc

Error on line 8 : d1 p002 n003 ledred
Unable to find definition of model "ledred"
Direct Newton iteration for .op point succeeded.

Date: Sun Aug 22 04:17:02 2021
Total elapsed time: 12.015 seconds.

tnom = 27
temp = 27
method = modified trap
totiter = 3680
traniter = 3667
tranpoints = 1640
accept = 1478
rejected = 162
matrix size = 20
fillins = 2
solver = Normal
Matrix Compiler1: 1.36 KB object code size 0.4/0.3/[0.3]
Matrix Compiler2: off [0.2]/0.5/1.1

 

[crutschow]

Error on line 8 : d1 p002 n003 ledred
Unable to find definition of model "ledred"

Just use an LED model that you have in your LTspice library.

 

[rjenkinsgb]

Not so faithful.
I'm using a PNP to drive the LED, not an NPN.

Exactly.

 

[Buk]

Just use an LED model that you have in your LTspice library.

I have an LTSpice library?

That's why I used Falstad to demo for sxy; no dependancies. (Nor steep learning curve; nor stupid UI;...)
(+ visual indication of current flows and rates; mouse over scoping;...)

 

[Buk]

sxy,

See here for a working Falstad implementation of Crutschow's XOR/XNOR circuits. Note that the XNOR version is the XOR + a NOT gate to invert the output.

 

[danadak]

Okay.
It would appear that the bottom two circuits are the same except one uses four discrete diodes and the other uses a four-diode bridge.

So you don't consider diodes to be an active component?

Ask HomeX

homex.com

Is diode active or passive?

Answer (1 of 34): TL;DR — the diode is a passive device. It is a nonlinear “positive” resistor, whose I-V characteristics lie in the 1st and 3rd quadrant of the I_D-V_D plane (see picture below), and by definition positive resistors are passive elements (they always dissipate power/energy — note ...

www.quora.com

Regards, Dana.

 

[crutschow]

I have an LTSpice library?

Yes.
Right-click on the LED and then select Pick New Diode (below).

See here for a working Falstad implementation of Crutschow's XOR/XNOR circuits.

Glad you finally got it to work.

 

[crutschow]

Is diode active or passive?

Well, it seems strange that a vacuum-tube rectifier is considered a passive device.

 

[danadak]

Definition(s) -

Introduction to electronic compontents: Active vs. passive components

(Bild: Public Domain) One key factor that differentiates types of electronic components from each other is whether they are passive or active. However, many people are unsure of exactly what that difference entails. This article is here to help.

www.power-and-beyond.com

https://www.arrow.com/en/research-and-events/articles/active-vs-passive-components-in-electronics

Regards, Dana.

 

[crutschow]

Definition(s) -

Introduction to electronic compontents: Active vs. passive components

(Bild: Public Domain) One key factor that differentiates types of electronic components from each other is whether they are passive or active. However, many people are unsure of exactly what that difference entails. This article is here to help.

www.power-and-beyond.com

https://www.arrow.com/en/research-and-events/articles/active-vs-passive-components-in-electronics

That states a diode is an active device.

So take your pick.

 

[danadak]

As you can see there is no biblical definition of active versus passive.

But that guys def leaves one to wonder why he considered diodes as active

In a nutshell, active components can, generally speaking, inject power into a circuit and are capable of electrically controlling and amplifying the flow of electrical current, whereas passive components cannot.

Of course we can spend a year or two debating what applies to what in the above def.....UGH.

Here they are considered passive, but then broadly classify tube's as active, would that
also be true of tubes with no elements, no connections. Silly.



But then -

Is a diode an active or passive device?

Whether diode comes under active or passive device ...

www.researchgate.net

diode is active or passive and why?

diode is active or passive and why?

www.allinterview.com

Lets debate this until neither of us is breathing anymore.


Regards, Dana.

 

[crutschow]

Lets debate this until neither of us is breathing anymore.

Naw, I'm good.
I don't have enough breaths left anymore to use them for that.

 

[Visitor]

Naw, I'm good.
I don't have enough breaths left anymore to use them for that.

Why stop now? This thread is only 3 pages long so far.