on "standard" items i just buy. i recently purchased a 3MHz Instek GFG8219A function generator. does lots of things... funny though, i needed it for square wave with variable duty cycle up to about 70Hz. i'll used the advanced features some day. things i cant buy i build. most of the time, for off-the-shelf items, its cheaper to buy than build.

but of course, kit building is fun and educational.

 

DC,

I agree with your philosophy to buy OTS when affordable, and construct when it isn't. But since I am largely unaware of all the OTS electronic parts and equipment that are both available and affordable to suit my needs, I try to seek help, even if that help means I still have to fabricate something. I've sought help here and the folks have come forward to offer their help. That's what makes this such a great community, and I am truly grateful for that.

For example, the 3 Mhz Instek GFG8219A function generator is something whose existence I was unaware of. The specs look decent, and I am happy to learn of it's existence, but its cost is a bit steep for me at this time. I do thank you for bringing it to my attention.

Mark

 

Hmm. I discovered that I actually had a TLC555 timer I'd bought from Radio Shack a number of years ago.

Tell ya what -
DC Kid, send me the Instek GFG8219A function generator. I'll wring it out for you. In the meantime, I'll send you something that'll meet your circuit requirements precisely

In exchange, I'll send my TLC555 to Marko, and he'll be happy too.

Everybody's a winner!

Seriously though, I'd found a signal generator that had a range of 100kHz-450MHz for under $300. That's a very attractive price. You'd be hard-pressed to find a digital model that would cover that frequency range in that price range. Today, at least.

A milestone was reached not long ago - the makers of the PIC microcontroller announced that they had sold their six billionth uC.
Did the purchaser get fries, too?

 

Hey Sarge,

thanks for the heads up on the signal generator. Dunno what under $300 is, but it probably is still a bit rich for me. Besides, the low end frequency is 100 KHz, not 1 Hz.

About that TLC555; I found a chip for a low price. Of course I don't know how clean the output is through the entire frequency range. Guess I really need an O scope too. Argggg.

Speaking of PIC microcontrollers, are those the best ones? Not that I'm even ready to deal with them yet, but just curious.

Mark

 

Dunno what under $300 is, but it probably is still a bit rich for me. Besides, the low end frequency is 100 KHz, not 1 Hz.

You'll find that when the high-end frequency goes up, the low-end does too - even on high-end machines. I was using an Agilent network analyzer at a former employer; it had a range of 300kHz-20GHz. It had a sticker price of $50k.

About that TLC555; I found a chip for a low price. Of course I don't know how clean the output is through the entire frequency range.

You can get TLC555's at your local Radio Shack for $1.69. As far as how clean it will be through the frequency range - that'll largely depend upon the components you surround it with, and your layout.

Guess I really need an O scope too. Argggg.

I've picked up a couple O-scopes on E-bay, both 60MHz models; a Hitachi V660 for $5+$35 shipping and a Tektronix 2215 for $40+$35 shipping. Both had small problems, but that's why I could get them for so little. They're older scopes, which is "a good thing" for tinkering at home, as you can repair them. I made certain that I could download the schematics and calibration procedures prior to purchasing the units. It's a good idea to replace ALL of the electrolytic caps with fresh low-ESR caps, or when they blow, they can take out surrounding components along with damaging the PCB (which can be tough to fix).

The Hitachi has a scope "bloom" in one corner, which to me is an indication of a partially collapsed control grid, internal to the video tube. Attempting repair of that would be dicey, involving opening the sealed glass enclosure. I'm going to leave well enough alone for now. The Tektronix has a dead channel 2, not really a big deal to me, as I've mainly been using the Hitachi. It's not going to be a big deal to fix the Tektronix, but the Hitachi takes up a bit less space on my bench.

The newer computerized scopes are great, but you can't fix them at home, and are EXPEN$$$$IVE to get repaired and calibrated.

Speaking of PIC microcontrollers, are those the best ones? Not that I'm even ready to deal with them yet, but just curious.

Whatever is "best" is what fits your requirements and pocketbook.

PIC mcu's made by MicroChip are very popular due to their low cost and broad range of options. They've had 8-bit and 16-bit mcu's for a while, and have recently introduced a 32-bit 80MHz mcu with up to 512kb flash mem and 32kb RAM with 16 ADC channels onboard. That's pretty impressive. No pricing data yet.
http://www.microchip.com/

Atmel has an interesting and broad line of mcu's.
http://www.atmel.com/products/

ST Microelectronics has quite a broad selection in a number of different architectures.
http://www.st.com/mcu/
If you register on ST Microelectronics' site, you might be able to get a few free samples. Free is always good.

Parallax makes a line of mcu's, but they're comparatively pricey:
http://www.parallax.com/
I bought a BS2sx and a BS2e a decade ago to play around with. There are better values available elsewhere, but Parallax does have great documentation and support for what they sell.

 

do appreciate your contributions, studiot. Not to offend

Nah, I'm not offended



It's just that the subject of signal generators is so huge, second only to that of audio amplifiers with electronics engineers.

I heartily recommend that you get hold of Elektor, March 2007. There is a review of lots of current function generators, a good discussion of different types of function generator and a reference to their original XR2206 based 2 Mhz generator (they sold 10,000 circuit boards) and it's 1984 update. You can download the original article free or get the mag.

http://www.elektor.com/cart.588.lynkx?event=AddToCart&productId=6447&quantity=1

 

About the commercial function generators, I hear ya Sarge. That is one reason why I started the thread introducing a more fundamental approach (Wein bridge fabrication), for a possibly more affordable solution.

And yes, I found the TLC555 at Radio Shack, as well as other places. Once again, if I only knew the components to surround it with and elusive layout that would provide that cleanliness…

I've tried to get O-scopes from ebay, but invariably get outbid, even though I've put up good money. Still, I'll keep trying. Don't know what else to do.

Thanks for the poop on the microcontrollers. I'll have to wade through the links to edgy-cate myself better. A battle for another day.

Mark

 

Hey studiot, slogging through other old threads, I am indeed seeing the hugeness of signal/function generators as a subject. Amazing, and yet the panacea solution is so elusive.

Thanks for that magazine link. I was able to locate the name of the article, but for some reason, I could not find it as an available download, unless I'm missing something (entirely possible).

Mark

 

There's 11 pages in the article, too much to post here. Send me a pm with an email address for a scan.

here's a snippet below.