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rhb:

--- Quote from: kt11 on April 17, 2016, 02:45:24 am ---I was also planning on doing the same thing, but with the previous version of the books which I had to purchase while in school. However, I just learned about this new version today. For those that have experienced both the second and third edition, what are your opinions on whether or not it's worth it to pick up the most recent version?

--- End quote ---

I bought and read the 2nd ed years ago.  I was on the verge of writing a letter to the authors begging them to update the book when the 3rd came out.  It's well worth the money.  But I'd keep the 2nd as you might well find that some useful information is mentioned there but not in the 3rd.

A lot of the parts mentioned in AoE 2 are *very* hard to find.  And there are much better options for a lot of things.  I'd like to suggest "Electronic Principles" by Malvino and Bates.  Don't get the current edition as it is insanely expensive.  AoE is pretty advanced for a novice.   The original target audience was physics students embarking on a PhD in experimental physics.  So H&H wanted the book to focus on what the mathematics *didn't* tell you.  But they really do presume you know all the math already.

I worked through the 2nd ed of "Electronic Principles".  Unlike many authors, Malvino went to the trouble to actually construct *every* circuit published to make sure there were no typos.

FWIW It is my understanding that the the AoE lab manuals are riddled with typos.
rhb:

--- Quote from: akos_nemeth on January 23, 2017, 10:10:28 pm ---
--- Quote from: stoica adrian on January 01, 2017, 08:19:35 pm ---Hey guys, i need your help.
@ lab 4 in ''learning the art of electronics''' is a design exercise.
They say to design an AM radio receiver.
For the radio you  have to use use a long antena ( about 30 feet in the air using a long cable) or you can use a high frequency amplifier instead of the 30 foot antenna

My request is: can someone recommend a schematic to make this high frequency amplifier for this design. I had found a lot of schmatics on google,
but i don't know what to choose.

Thanks,

--- End quote ---

Hi Adrian,

I found this schematic for the short antenna problem:http://learn.mikroe.com/ebooks/radioreceivers/chapter/simple-radio-receiver-with-lm386-ic/


It uses the LM386 jellybean audio amplifier IC.
Do you have a tuning variable capacitor? They are not sold by Farnell, TME, Mouser, but I have seen in amazon.co.uk: https://www.amazon.co.uk/Spiratronics-CR3-016-Miniature-Tuning-Capacitor/dp/B0093Z0VP2/, also ebay has many tuning capacitors, but the real oldschool ones are not cheap...

Regards,
Ákos

--- End quote ---

That circuit provides gain at audio.  A common way to get gain at RF in a simple radio is to attach the gate of a JFET to the antenna. 

http://www.techlib.com/electronics/antennas.html

This is what you want:

[

You can reduce it to a single transistor by breaking the circuit at the base divider of the 3904.  But the circuit shown is worth building in a small box for future use as a bench tool.  It's *very* basic, but a lot of times that is all you need.  Use a pair of  female  BNCs and a barrel connector and add an LED to indicate that it has power.  Leave off the switch unless you choose to use a battery.  But do yourself a favor.  Put labels on the box.  I've found a bunch of such things I built 30+ years ago and which I now have no idea what they are for.

You should analyze the circuit to determine bias points, currents, etc.

FWIW I'm 65 and recently allowed myself the indulgence of buying over $10K of T&M gear.  So what have I built lately?

A continuity tester powered by a AAA cell in a small box with a 1.5-3 V buzzer from allelectronics.com and two banana jacks so I can safely trace 1.8 V logic level circuits.  My HP 34401As supply ~7 V for the continuity test.  That's a recipe for causing serious damage trying to trace modern logic.

The next project was a level shifter in a box with 8 banana jacks using this board:

https://www.allelectronics.com/item/llc-46/logic-level-converter-bi-directional/1.html

A pair for each logic level and then the 4 logic signals. $3 of electronics in $10 of box.

Let's suppose you have a piece of test gear with a CPU and ROM and it's not working because one of the ROM address lines is a bit flakey and ROM images are not available.  So you *really* need to read the flakey ROM.  By connecting the problem address line Vcc to a bench supply you can bump up the voltage of that one address line a few percent above the normal logic level and see if you can dump the ROM with a logic analyzer.

I'm doing another one with DB-9 connectors for RS-232 conversions.  That will require special cables, so it will all eventually go into a small storage case with instructions on using it.  I was rather dismayed to go though a box of stuff I'd built 30 years ago and realize I had no clue what they did.

I've designed more complex stuff, but I needed these gadgets.  The 1.5 V buzzer won't trace into a BGA, so I'm contemplating a pulsed LF signal and a detector version to handle that.  A test bench version of the signal tracers they sell for sorting out telephone wiring.

Ask good questions and you will get good answers. Ask poorly thought out questions and you will get answers of equal quality.  There are some *really* smart people who hang out here because they enjoy talking about this stuff.
rstofer:
There are some much simpler radios, some as simple as a single diode and a 30' antenna.
https://electronics.howstuffworks.com/radio9.htm

I couldn't find the lab in my 3rd edition - I must have just  been looking in the wrong chapter.
rhb:
The lab manual is a separate book.

The OP's question was about adding an RF (high frequency) amplifier, not an AF amplifier.  so the prior answer was going in the wrong direction.

As I have suitable parts on hand, I think I'll build the circuit I posted for my own use.  It's *very* basic, but for a general purpose RF amplifier for LF to VHF it's certainly satisfactory if carefully built Manhattan style.
rstofer:
Well, I don't think so.  We have some voltage drop across the ballast resistor based on collector current, we have Vf of the LED and that's going to be a couple of volts (usually), we have VceSat for the transistor (on the order of 0.2V) and, once this is all worked out, we can figure Ic

Let's take some 'pretend' numbers like Vf = 2.2V.  Then 3.3V - 2.2V - 0.2V - (330 * I) = 0

330 * I = 0.9V so I = 0.9 / 330 = 2.7 mA - probably not going to be enough to light up the LED - check the datasheet.

Looking at the base,we have 0.7VbeSat so we're thinking about 2.6V drop across 10k or 0.26 mA so we need a minimum Beta of 10.4.  Ic / Ib

Now, we need to know the real numbers:  What is Vf of the LED?  What is VbeSat of the transistor?  What is VceSat of the transistor?

Anyway, that's the way I would approach it.  I have no idea what the books expects.
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