Normally the PNP using in the high side and NPN using in the low side, why they used PNP in the low side

When do you using a PNP switch for sinking? when the output of an Op amp or Logic Gate is Negative voltage?

When do you use a PNP switch for sourcing? when the output of an Op amp or Logic Gate is + positive voltage?

When do you use Transistors switches for sourcing or sinking? I'm not sure when to use them for the right function

Because some circuits use transistor as switches to do sourcing and other circuits use transistors as switches to do sinking

So how do you know when to use it for sourcing or sinking?

 

When do you using a PNP switch for sinking? when the output of an Op amp or Logic Gate is Negative voltage?

When do you use a PNP switch for sourcing? when the output of an Op amp or Logic Gate is + positive voltage?

When do you use Transistors switches for sourcing or sinking? I'm not sure when to use them for the right function

Because some circuits use transistor as switches to do sourcing and other circuits use transistors as switches to do sinking

So how do you know when to use it for sourcing or sinking?

The Transistor's Sink And Source.

 

Scott thanks for the time to make the Chart

But i do need help with the theory oh these questions

When do you using a PNP switch for sinking? when the output of an Op amp or Logic Gate is Negative voltage?

When do you use a PNP switch for sourcing? when the output of an Op amp or Logic Gate is + positive voltage?

When do you use Transistors switches for sourcing or sinking? I'm not sure when to use them for the right function

Because some circuits use transistor as switches to do sourcing and other circuits use transistors as switches to do sinking

So how do you know when to use it for sourcing or sinking?

 

Scott thanks for the time to make the Chart

But i do need help with the theory oh these questions

You have to study how the circuit working not just see the meaning of source and sink, the answers are there.

 

But i don't get when or why the transistor as a switch is sinking or sourcing

It depends on what the Voutput's polarity?

 

But i don't get when or why the transistor as a switch is sinking or sourcing

It depends on what the Voutput's polarity?

Did you see the input waveforms?
Those are the answers and I also mentioned that how to google, those can let you to know more details.

 

Sourcing and sinking refer to the function a transistor is performing. When sourcing, it is supplying voltage to the output as in an emitter follower circuit. When sinking, it is depriving the output of voltage as in having a transistor with the emitter tied to ground and the output taken from the emitter. A pull-up resistor would be supplying the output voltage until the transistor turns on, then the transistor would "SINK" the voltage to near ground level.

As to having an AC signal going to the input of the 4053 and a DC signal on the output of the OP amp U37, you need to look at the control signal of the 4053. It may be that it is a signal of the same frequency as the AC input. The fact that the input for the 4053 says it is from ELEV SERVO tells me it is probably a phase shifted sine wave. By switching the 4053 on at a precise time, such as the 90 degree point of a sine wave, both the amplitude and phase of the input can be sampled. This value would be added to the various other inputs such as pitch rate and pitch disp (I assume disp means displacement).

The above is just a lot of guesswork but it would help to know what the PHI ELEV signal looks like.

 

Sourcing and sinking refer to the function a transistor is performing.

Yes I understand this

But what I don't understand it when do you use transistor switches to sink? and when do you use transistor switches to source?

What are some rule of thumbs?

When don't you want to use a transistor switch to sink or source because it might false trigger an digital IC gate or it might damage the next stage or false trigger it

There is 2 types of sinking
1.) Sinking the emitter
2.) Sinking the collector

What is the difference when a transistor switch sinks the emitter VS sinks the collector?

There is some circuit that use transistor switches to sink the emitters output
and other circuit they use the transistor switches to sink the collectors output
What is the names of these two types?
What are the differences between the two please?

 

If you are in the repair field, you go with what is already designed. Strive to understand the basics and how they apply to what is in front of you. Trying to second guess the "why" of the design will drive you and everybody trying to explain the "why" nuts.
My kids stopped asking, "But why, Dad" when they were about 8 years old.

 

I'm not trying to second guess the design

I'm just saying I have seen both kinds of sinking

I'm sure some techs here have also , it seems common

 

I spent a lots of time to drawn the circuits and used it tried to tell you what you want are there, but it seems you just let it pass by, no any question about the circuit and just continuing asked the same things, but the answers are there already.

 

I spent a lots of time to drawn the circuits and used it tried to tell you what you want are there, but it seems you just let it pass by, no any question about the circuit and just continuing asked the same things, but the answers are there already.

No surprise. It rather seems that Dexter and his aliases are some some sort of bot programmed to continually ask variations of the same electronic question over and over to see how long forum members will continue to try to answer the question, until finally everyone quits in exasperation. Then the bot starts a new tread with a different question.

 

No surprise. It rather seems that Dexter and his aliases are some some sort of bot programmed to continually ask variations of the same electronic question over and over to see how long forum members will continue to try to answer the question, until finally everyone quits in exasperation. Then the bot starts a new tread with a different question.

Asking the questions is ok, but the forum is an interactive environment, we need the Q&A come and go, if the op there is no normal response, what should we do?

 

I have had some major trouble on another forum because of the op, but in view of some things he has said recently on here my opinion has changed.
I can see why exasperation with him, and I understand why people get fed up, I DID in a BIG way.
But I have read many pages he has written all over the net. My guess is he is something to do with repair/restoration, isnt THAT old but has had over 20 jobs in the electronics field. SO, I thin the following is a pretty good guess.
He is way out of his depth, his education had a stumble, he doesnt know enough to keep the jobs he gets. BUT he has a job, clearly wants to be good at it, spends alot of time and effort in trying to keep his job.
Needs help (alot of it), I personally think the way the questions are put says he is desperate. So Dexter please slow it down, explain exactly what is going on. Keeping everyone in the dark is a bad idea. To everyone else I have gone from a big dislike to thinking if he can reign it in a bit, then it would be rather neat to train a guy over the net, and help him keep his job.
20 jobs in 3-4 years (i think thats right). He must really want this badly or by now most would have given up and be flipping burgers (I love that american expression).
I do feel really bad for him, but first I think he needs help in ASKING questions!

 

I do feel really bad for him, but first I think he needs help in ASKING questions!

Yes, there needs to be some how to on asking questions that others can understand, and another one on answering questions that others ask. Without that this is going nowhere.

 

Yes, there needs to be some how to on asking questions that others can understand, and another one on answering questions that others ask. Without that this is going nowhere.

Yes, In Taiwan we called that the Chicken talking to the Duck.

 

One thing that is beginning to disturb me is the fact that, by forum rules, help a person change from incandescent bulbs to LEDs in the dash lights on his car but we can try to help someone understand how an aircraft autopilot works so he can try to fix it. Check the OP's multiple threads and the signal names on schematics he has posted.

 

Bill, I don't think that the rules here forbid looking at automotive schematics and discuissing how it works, only their modification which hopefully is not Dexters final goal with these. So even extending the rules to airspace modifications won't help much here. But anyway this is up to the mods to decide.

 

I agree it is up to the mods to make the decision. Dexter has stated the other techs he works with have more experience, therefore he must be working on these systems. Why he doesn't ask the other techs to explain the systems is a mystery to me. They would be in a much better position to help him.

 

Well from many past post all over the net, he does get some help from his boss and other techs, I dont think these are flying aircraft?? To me it sounds more like restoration.
Anyway, how safe is a aircraft from the 60's or 70's to fly even in perfect condition??? You wouldnt get me on one without all the LEDS,BOINGS, and the chip that goes PULL UP, TOO LOW PULL UP, PUL...........
I mean the 60's!!!!!my dad was born in the 60's! thats so old surely they have all disintegrated into dust by now (a bit like dad )