I recently started teaching myself electronics in my spare time with the help of "The Art of Electronics" and its student manual. I have worked my way through the first chapters, but I have some questions; since I have no teacher to ask, I hope it's okay that post my questions here. :-)
First of all, I bought a lot of test equipment that I hope will suffice for most of the lab exercises.
EP-613 DC power supply (0-30V/2.5A variable output, and two fixed 5V/12V outputs)
GFG-8215A function generator (0.3Hz-3MHz, sine/triangle/square/ramp/ TTL/CMOS output, -20dB att.)
Caltek CM2701 digital multimeter
I assumed that this would suffice, since AoE is an introductory text and therefore probably wouldn't require very expensive equipment. But already in lab 2-4 the text assumes that the function generator has a "sweep" feature that I just discovered is missing on my 8215A. How important is this feature? Will this become a problem in later exercises?
That's good to hear. I probably should have posted the equipment list for comments before I went out and bought everything, but apparently, it turned out okay in spite of that. :-)
Ah, I didn't think of that; thanks for the tip! I think I can manage without the software, since I can program the sound card myself. Of course, the sound card does not have the frequency range of the function generator, but that's okay -- I'm mostly in this for fun and educational purposes. And speaking of the frequency range: I used to think that the 192 kHz sample rate offered in modern sound cards was ridiculous, but now I can finally see how that could be useful. :-)
You have chosen wisely -- I wish I'd just bit the bullet and purchased the equivalents to these when I was starting out -- it would have made the journey a lot easier.
Another post said you might want to look at just tweaking the frequency manually. That's a good idea -- I haven't used a sweep function since I don't know when. But, the data sheet for your function generator says it's got an external voltage-controlled frequency input, which might do the trick if you're desperate for a sweep. The VCF has 100:1 sweep range for 0 to 10V input, which is probably far more than what you need. You might want to cobble together a sawtooth generator and add it to a 5V reference so that the amplitude and frequency of the sawtooth meets your needs (you'll probably want 5VDC with an
0.1V p.p. sawtooth). Input this to the VFC input, tweak to taste, and you'll have your sweep. You can do this with a 9V battery or your fixed 12V supply, and an LM358 dual op amp and a handful of components.
A _lot_, but I managed to justify it to myself by considering the countless hours of fun it will give me and, eventually, valuable knowledge that I can put on my resume. Compare this to all the other junk we spend money on, and then it doesn't look so bad. :-)
Anyway, here you got it, all in USD (prices exclude the 24 % Norwegian sales tax):
Scope 1875 Power supply 160 Function generator 280 Multimeter 35
In addition to the above list, I also bought a soldering station¹, a breadboard², bananjacks, wire, extra probes for the multimeter (one pair with sharpened tips and another pair with grip hooks), a roll of wire to connect things on the breadboard, a set of resistors (10 ohm - 1M), and a set of ceramic capacitors (1.5 pF
- 2200 pF). I didn't mention this in the original post, since the soldering equipment for the most part isn't required (the breadboard is solderless), I know I am happy with the breadboard, and I figured the rest wasn't very exiting. But I do have one question regarding the capacitors; in the RC circuit in exercise
2-1, the text specifically mentions that the cap should be mylar, but I used ceramic caps and I think I got good results with that. So, for a trivial circuit like this, why bother specifying mylar caps? (The table on p. 22 states that mylar has better accuracy and leakage, but I would expect the margins to be pretty good here.)
¹ Solomon SR-976; I paid about $75 for this.
² RH-74; $54 It's the larger one in
Mylar is pretty much the same, world round, (with exception of internal inductance and resistance, which depends on how the wire leads are attached to the metal) but ceramic caps come in a wide variety of types , some with very different properties.
Low value ceramic caps, like you list are probably low-K (NPO COG, X7R) types that have pretty linear capacitance versus voltage, low dielectric absorption and low microphonics, but larger values are more likely to be high-k types (Y5V, Z5U) that have terrible properties in all respects except for size.
If you can live with audio range, try my DaqGen freeware at . It does all kinds of function generation using a standard Windows sound card. Besides sweeps, you can do AM, FM, Burst, PWM, and phase modulation. You can choose from standard waveforms or various types of noise, or you can supply arbitrary waveforms or even play regular WAV files... with full modulation. There are 4 output streams per DAC channel, and they may be used independently or a stream can be used as the modulation source for another stream. (For example, you can have an Arb wave providing the AM modulation for a Gaussian noise source.)
Extensive Help system is built in.
Best of all, it's completely free!
Bob Masta dqatechATdaqartaDOTcom D A Q A R T A Data AcQuisition And Real-Time Analysis
Yikes! $1875 + 24% = $2325! A TDS2012 is $1595 here, plus 7.5% state sales tax, which you can finesse by buying it out-of-state. As a company purchase, we can expense it and get back almost 50% as a tax deduction, so it really costs us about $900.
Why don't governments tax the useless crap, and give people a break on productive/educational stuff?
Food here is not taxed, unless it is "ready to eat", like a hot sandwich. I just bought a Hershey chocolate bar with almonds (about the best standard American chocolate, barely acceptable at that) and it wasn't taxed. The distinctions can be tricky, but most stuff in a supermarket is not taxed. Sales tax here is 7.5%. Books are taxed, but newspapers aren't. Beer is, fruit juice isn't.
If you locate a US supplier that has those tips in stock, and give us their contact information and stock number or a link or whatever, I'll buy a few and send them to you. Despam my email address to send the info.
:-) Actually, the only reason I paid the "modest" sum of $1875 was that I purchased the scope from Farnell instead of ELFA, and Farnell will usually only deal with other companies. If I had got the scope at ELFA, I'd have to pay $2310 + 24% = $2864 (= ouch!)
By the way -- does anyone here regularly buy equipment at a place that sells the Solomon SR-976 soldering station? I recently discovered that my only local vendor, ELFA, do not sell the 0.3mm tip (part number 976T-SB). I asked them about it, and they said that people who got the cheap Solomon soldering stations were not interested in fine tips -- people who are use the insanely expensive Weller products. I found some web shops that sell this tip, such as
but unfortunately, they will not do international orders this small. So, I was wondering if there are anyone here who could pick up a couple of these tips and send them to me. Of course, I would pay in advance for all expenses and gladly throw in a little extra for the trouble. If anyone is interested, please send me an email.
At least they don't tax books here in Norway, and the tax on food was recently halved. (Unfortunately, it didn't make much of a difference for us customers, since the supermarkets soon decided to raise the prices accordingly. :-) I wish tax exemptions such as these would cover all productive/educational products, but it will probably never happen because it would be difficult, and a lot of work, to classify everything.