Monday, May 10, 2010

Experiments 29 and 30

Experiment 30 builds on Experiment 29 - unfortunately, I've had some bad luck getting the proper components for these 2 exercises. Exp 29 calls for 100 microfarad capacitors of the nonpolarized electrolytic type... ditto for 47 microfarad. I thought I'd ordered the proper BP type capacitors... apparently not.

One thing I did notice about Experiment 29 was that it calls for two 47 microfarad capacitors but they're not seen in the actual schematic on page 251. I do see in the schematic two 0.15 microfarad capacitors... I don't have those either... added to the shopping list. You'll also see a 10 microfarad NP capacitor that's not listed in the experiment's shopping list... argh.

I've called ACK supply and I believe I can get the right components this week, but I'm not driving to that part of town until Wednesday... so Exp 29 and 30 are on hold temporarily. (In the meantime, I've read over Experiment 31 and believe I can go ahead with that one while trying to get the capacitors.)

I'll also need to pick up the headphone socket seen in Figure 5-42 - this isn't on the shopping list either. Thankfully, I purchased one of those big bags of resistors so I've got those covered, including the TEA2025B chip required. Again, sorry for delays, but I'll get back to these two experiments soon.

On to Experiment 31...


  1. good work!!

    keep it up, this blog has helped me to a whole new level of electronics!

    cheers :)

  2. James, as I mentioned in the book, you can put two regular electrolytics together (in series with opposed polarity) if you can't find a nonpolarized type.

    I'm a little puzzled that you are still trying to use local sources. Wouldn't it be easier to order a bunch of parts all at once, by mail? E.g. by searching "capacitors electrolytic assorted" on eBay I found a set containing 245 capacitors, values ranging from 1 to 4700 uF, from West Florida Components, for less than $30 including shipping. That's about 10 cents each! Of course you may not want to spend $30. But you'd have all the electrolytic capacitors you'd need for a year or two of experiments. Just a thought....

    I do apologize for the lack of coordination between shopping lists and schematics.

  3. Charles, no apology necessary - unlike the previous chapters, I did not read through all of chapter 5 and highlight the parts that I knew I didn't have... instead, I chose to buy them one experiment at a time, which was a bad idea.

    Until I finish the book and figure out what area of electronics I'd like to explore, I'm hesitant to spend money on buying large quantities of parts... even though I'm sure I'll end up using most of them.

    I've got a post I'm ready to put up today that contains some snippets of our discussion about buying parts... your comment reminded me I needed to get that up for the readers.

    Even though I understood your explanation of using regular electrolytics, I wanted to use NP as the schematic uses. I picked them all up yesterday and am going to put together exp29 today.

  4. Guys, with respect to sourcing components, I've found a place called "Futurelec" They're dirt cheap. I picked up 50 of every 5% 1/4w value resistor between from 100-1M ohm, various diodes and electrolytics and six 7-segment LED displays. all for about $35. Resistors worked out to a penny a piece. Quality all seems good. The downside; it took a very long time to receive the booty - this seems to be a complaint of most customers. My order took just under 30 days to come in. However, it was fulfilled from Thailand and shipped as the Iceland volcano disaster was playing out - so YYMV.
    If you need parts right away, this place is a no-op, but for stocking up inventory, I haven't found any place cheaper. Hope this helps.

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