answers

[mstechca]

Please make sure that every user that has read my answer(s) or questions is able to view this particular post BEFORE trashing it.

A number of you may be thinking about the answers I wrote, especially recently.

I have been rejecting (if you want to call it that), some answers because they don't seem to help. In fact, almost all answers come with no explanation. Worse yet, I get answers which require me to use a completely different, and more complicated circuit or an IC.

As some of you know I was a student at college, but now I am not because I can't afford a CENT for it! (even though I am working, and paying rent). When I do buy electronic components, I buy them cheap.

The problem with getting different circuits as answers or "change this...", "change that..." as answers is that I have to throw money in the garbage! (piece of a circuit board + whatever other components I can't get off).

If I can be explained WHY a certain configuration works over another, and WHY I shouldn't use a particular one, then I can understand better.

so the key thing here is the answers to the why

I'm not sure if this is the place for me.

 

[Optikon]

Please make sure that every user that has read my answer(s) or questions is able to view this particular post BEFORE trashing it.

A number of you may be thinking about the answers I wrote, especially recently.

I have been rejecting (if you want to call it that), some answers because they don't seem to help. In fact, almost all answers come with no explanation. Worse yet, I get answers which require me to use a completely different, and more complicated circuit or an IC.

As some of you know I was a student at college, but now I am not because I can't afford a CENT for it! (even though I am working, and paying rent). When I do buy electronic components, I buy them cheap.

The problem with getting different circuits as answers or "change this...", "change that..." as answers is that I have to throw money in the garbage! (piece of a circuit board + whatever other components I can't get off).

If I can be explained WHY a certain configuration works over another, and WHY I shouldn't use a particular one, then I can understand better.

so the key thing here is the answers to the why

I'm not sure if this is the place for me.

MSTECHA, if you do not like the answers you receive, then ask for further explaination or ignore them! You have every right to make up your own mind and often, there is some misunderstanding involved which exacerbates the situation.

If you are on a very tight budget and have to think twice about trashing something, then it is up to you to be especially careful about getting to the bottom of things. Also, people are lazy. People would much rather say it sucks than to give a detailed explanation for how they arrived at that conclusion. But, if you ask for the explaination, you'll probably get it. Don't blindly follow advice. Do whatever it takes until it makes sense to you (or not) then choose. It's all part of the learning experience. Learning new & exciting things about electronics doesnt have to cost much money but it might cost ALOT of time invested. Consider slowing down & going back to basics occasionally while you pursue understanding..

 

[Nigel Goodwin]

You can't expect a five year course as the 'why' for an answer?, you've been given plenty of 'why' answers - but you simply ignore them - presumably because you don't understand the answer?.

The reason you don't understand is because you haven't got the basic knowledge required to let you understand, and you don't seem interested in trying to acquire it?.

To put the situation in perspective, it's very similar to this:

You want to dig your garden, say to plant potatos?, and you decide to use a banana to do so!. All us 'gardners' tell you that's completely the wrong implement, you should use a spade.

You completely ignore everyones advice, but continually ask for advice on using a banana to dig your garden.

This is EXACTLY what you have been doing!, except in electronics.

 

[Optikon]

On another note,
I find myself in your situation all the time. Sometimes trashing everything and starting over is the right thing to do! Something is learned by those experiences though and next time around, you'll be much better informed.
If I had a nickel for ever time I trashed a whole concept/idea/design/calculation etc... and started over from zilch, I'd be
"independently wealthy."

 

[audioguru]

MStechca,
We DO explain WHY your circuits don't make cents (sense):
1) A super-regen isn't a real radio. It doesn't have a multi-tuned RF amplifier with AGC, mixer and local oscillator. It doesn't have a multi-tuned high gain IF amplifier also with AGC. It doesn't have an FM detector.
A super-regen overloads easily and has high noise and distortion. A real radio tuner has all these necessary things and doesn't need to tune to the side of an FM station to use an AM detector to "slope" detect it.
A super-regen tuner is a toy.

2) We explained WHY the outputs of a counter don't switch series capacitors in and out, which is necessary to tune your radios, and offered a simple and cheap varactor tuning method instead.

3) We explained WHY all electronic circuits have and need a supply bypass capacitor.

Rent? In your small town it is cheap. Come to the big city and see real rent prices. Of course in the big city well-paying jobs are numerous.
When renting you are throwing money away. You have a job so are able to buy a cheap house with a low-interest mortgage. Then you fix it up and sell it with a profit. I hope you don't have high-interest credit card debt, I never did. I never purchased anything I couldn't afford.

You're throwing away good parts because you can't get them off? When I was your age I invested in a temperature-controlled soldering iron and a solder-sucker with a piston in an aluminum barrel. 40 years later I still use them every day to remove parts from stuff that I usually get for free.

Electronics education? The web is full of good information. I learned a lot from magazines at the library.

I think you just need a little common sense and some good luck. :lol:

 

[panic mode]

mstechca,

don't be afraid to ask question until you get the answer that makes sense to you. just be persistent. this place is great with lots of knowledgable guys and very friendly atmosphere. i think i must be the guy with most rants so far (sorry everyone, i have short fuse...). not everyone will always find time for prompt answer but this is still much faster way to get an answer compared to alteratives. and i think most people here come to learn...

 

[akg]

..not everyone will always find time for prompt answer but this is still much faster way to get an answer compared to alteratives

Yup i totaly agree....

 

[danielsmusic]

if you are throwing away components that are good don't do the circuit in the first place. i do it on a simulation program, look at it while running to make sure there are no bugs and use cheep prototyping board to build it on.

i also use a soldering iron and solder-sucker with a piston. it works great!

 

[mstechca]

This is amazing. 7 replies in this post in less than 3 days.

You can't expect a five year course as the 'why' for an answer....

I wasn't asking for anyone to write a book (of answers).

To put the situation in perspective, it's very similar to this:

You want to dig your garden, say to plant potatos?, and you decide to use a banana to do so!. All us 'gardners' tell you that's completely the wrong implement, you should use a spade.

You completely ignore everyones advice, but continually ask for advice on using a banana to dig your garden.

This is EXACTLY what you have been doing!, except in electronics.

in this whole scenario, I would wonder why a spade is better than a banana, and how it is better. Since I know the difference, there is no need to answer it.

We DO explain WHY your circuits don't make cents (sense)...

at least you do.

It doesn't have a multi-tuned RF amplifier...

I see difficulties coming. I just want only one tuner, not two.

...with AGC, mixer and local oscillator.

It has a self-quenching oscillator.

It doesn't have a multi-tuned high gain IF amplifier also with AGC. It doesn't have an FM detector.

I can live with an AM detector.

A super-regen overloads easily and has high noise and distortion.

in 99% of the cases, yes. But I tend to control that by changing capacitor and resistor values.

A real radio tuner has all these necessary things and doesn't need to tune to the side of an FM station to use an AM detector to "slope" detect it.
A super-regen tuner is a toy.

toy, or not, if it works, that is all that matters to me.

We explained WHY the outputs of a counter don't switch series capacitors in and out, which is necessary to tune your radios, and offered a simple and cheap varactor tuning method instead.

If I use varactors, then I will have to buy more stuff and pay more

Why do you clain that VCC and ground are exactly the same at RF?

Rent? In your small town it is cheap. Come to the big city and see real rent prices.

Small town? LMAO
I live in a city of 500,000 people, thats about 1/4 of Toronto.

Of course in the big city well-paying jobs are numerous.

I got an OK job.

When renting you are throwing money away. You have a job so are able to buy a cheap house with a low-interest mortgage.

I understand, but I have my family to deal with. and I don't know if I get approved on a < $1000/month income.

Electronics education? The web is full of good information. I learned a lot from magazines at the library.

in general, yes. for the answers to "why this " and "why that " questions, no.

I think you just need a little common sense and some good luck.

I need more luck.

 

[audioguru]

It doesn't have a multi-tuned RF amplifier...

I see difficulties coming. I just want only one tuner, not two.

A good FM tuner has a tuned LC network at its antenna then an RF amplifier with AGC followed by another tuned LC network for good selectivity and freedom from overload.

Why do you claim that VCC and ground are exactly the same at RF?

Because the impedance of a 1000pf supply bypass capacitor is only 1.6 ohms at 100MHz. It is like a dead short.

 

[zachtheterrible]

A good FM tuner has a tuned LC network at its antenna then an RF amplifier with AGC followed by another tuned LC network for good selectivity and freedom from overload.

That could be done for mstecha's superregen.

 

[audioguru]

Hi Zach,
A simple super-regen uses positive RF feedback to get its gain. It is almost impossible to adjust the feedback to just below the oscillation point so it is allowed to oscillate then "squelch" its gain back down, build up the gain and squelch again at an ultrasonic rate. Therefore if it had an RF amplifier it would amplify its own radiation.

 

[jrz126]

You want to dig your garden, say to plant potatos?, and you decide to use a banana to do so!. All us 'gardners' tell you that's completely the wrong implement, you should use a spade.

What if he were to freeze the banana?
:lol:

 

[Nigel Goodwin]

You want to dig your garden, say to plant potatos?, and you decide to use a banana to do so!. All us 'gardners' tell you that's completely the wrong implement, you should use a spade.

What if he were to freeze the banana?
:lol:

Give it a try!, and let us know how you get on?.

 

[mstechca]

Why do you claim that VCC and ground are exactly the same at RF?

Because the impedance of a 1000pf supply bypass capacitor is only 1.6 ohms at 100MHz. It is like a dead short.

but 1.6 ohms isn't 0 ohms.

is there such thing as "RF heat"? because maybe that is what is happening.

I think I'll have to go with a high-impedance capacitor.

 

[audioguru]

but 1.6 ohms isn't 0 ohms.

It's much closer to zero than any other part of your circuit.
Why do circuits use a voltage regulator? Its output impedance is extremely low at lower frequencies, and a small ouput capacitor is used to bypass higher frequencies.

I think I'll have to go with a high-impedance capacitor.

Why? Then your oscillator and counter won't work.
ALL circuits need a low impedance supply bypass capacitor.

 

[mstechca]

I think I'll have to go with a high-impedance capacitor.

Why? Then your oscillator and counter won't work.
ALL circuits need a low impedance supply bypass capacitor.

I managed to pull off an LED circuit without a supply cap. Just connect a battery, resistor and LED (the right way) in series.

I wonder if it is to my advantage to connect an inductor and capacitor in series and make that my bypass component instead.

The inductor is opposite of a capacitor when calculating impedance.

 

[audioguru]

I managed to pull off an LED circuit without a supply cap. Just connect a battery, resistor and LED (the right way) in series.

I wouldn't call it an electronic circuit. It's just electrical.

I wonder if it is to my advantage to connect an inductor and capacitor in series and make that my bypass component instead.

Then it would be a good bypass at only its single resonant frequency. You need to bypass all frequencies and don't want resonance in a supply.

 

[mstechca]

I managed to pull off an LED circuit without a supply cap. Just connect a battery, resistor and LED (the right way) in series.

I wouldn't call it an electronic circuit. It's just electrical.

Playhookey.com and I have done a two-transistor astable multivibrator without a bypass cap. Do you call that "electrical" too?

I wonder if it is to my advantage to connect an inductor and capacitor in series and make that my bypass component instead.

Then it would be a good bypass at only its single resonant frequency. You need to bypass all frequencies and don't want resonance in a supply.

and if I replaced it with a resistor...

 

[Nigel Goodwin]

I managed to pull off an LED circuit without a supply cap. Just connect a battery, resistor and LED (the right way) in series.

I wouldn't call it an electronic circuit. It's just electrical.

Playhookey.com and I have done a two-transistor astable multivibrator without a bypass cap. Do you call that "electrical" too?

No, but it's only a simple circuit, and have you tried it over a large range of battery discharge conditions?.

Perhaps I'd better explain why ALL electronic circuits should have a supply decoupling capacitor (or more than one?).

Circuits rely on there being a low impedance path between the power rails, particularly at AC, and the capacitor provides such a path. It's extra important if it's in an early stage, where the power is fed through a series resistor - because the series resistor prevents such a low impedance path.

With a battery supply the battery itself gives a low impedance path, when the battery is BRAND NEW - as the battery ages it's internal resistance increases, and the bypass effect reduces. Adding a bypass capacitor across the supply both improves the effect with new batteries, and maintains the effect as the battery ages.

If you look inside an IR remote control you will find a fairly large electrolytic directly across the battery - with this you probably get 12 months life from the battery, without it you might only get two months use - it's that big an effect at times!.

I wonder if it is to my advantage to connect an inductor and capacitor in series and make that my bypass component instead.

Then it would be a good bypass at only its single resonant frequency. You need to bypass all frequencies and don't want resonance in a supply.

and if I replaced it with a resistor...

It would provide no useful effect, but would discharge your battery more quickly!.