I working on building a function generator build but I have found some design and figured I would ask what you guys think about each of the schematic and whats the best to build and use ???

1- I really like this circuit but I see no way to adjust anything beside the wave form and can this be added on too ???

2-The only problem I see is finding the max chip for cheap

3-This only produces Sine and Triangle waves

 

I'd start with #1, because learning all about the 555 is well worth your time.

You could change frequency in that circuit by changing the timing resistor R7 (and R1) and the capacitor C3. So replace R7 with a variable resistor.

 

Take a look at this chip http://www.exar.com/communications/timing/voltage-controlled-oscillator-vco/xr2209 Both xr2206 and MAX038 is obsolete, and high prized. But the xr2209 is still active. If you in the link I provided click on buy now. You will find out who is stocking this chip

 

Try the 8038 because it does everything you want at reasonable frequencies. There are two 8038 ICs available on ebay for $1.65

 

See ICL8038 data sheet. http://www.intersil.com/content/dam/Intersil/documents/fn28/fn2864.pdf

 

Use the XR2206 as it has all 3 wave forms, square wave is on pin 11.

http://eeshop.unl.edu/pdf/XR2206.pdf

see page 6.

 

Use the XR2206 as it has all 3 wave forms, square wave is on pin 11.

http://eeshop.unl.edu/pdf/XR2206.pdf

see page 6.

You can get them here:http://www.elexp.com/ics_10cn.htm
About halfway down the page...

 

Hi Dr. killjoy,

Strangely enough I've just built a function generator based on the ICL 8038, at least breadboarded it out.... It works really well, just some minor issues to iron out. Rather than hijack this thread I'll start a new one ;-)

I built #1 the Velleman version and its rubbish, the Dave Jones version is probably quite good, but the chip is exxxxxxpensive, the last one just doesn't hack it really.

Anyway, I've got a spare ICL 8038 chip, PM me your address and I'll stick it the post tomorrow! If you want that is. I used this design here.

All the best Steve.

 

I built my function generator using the XR-2206. It's still available.

https://www.jameco.com/webapp/wcs/s...storeId=10001&catalogId=10001&productId=34972

 

Remember that both the 8038 and the 2206 are meant for relatively low frequencies.

The 8038 runs out of steam at about 100kHz.

The 2206 being later and more expensive will get to a few hundred kHz depending upon your sample.

By this I mean that the output waveforms become rounded andindistinguishable.

Both benefit from constant current drive to the frequency programming terminal.

finally search this forum there has been a deal of discussion about both these ICs.

go well

 

I recently come by a complete collection of Elektor magazine from 1975 to about 1990. I remember seen a very detailed article about the xr2206 or ICL 8038. Cant remember which just now. Has to dig into it

 

The principle Elektor articles (XR 2206)
January 1978
December 1984
April 1987

Also see April 89 dual op amp based function generator.

Later articles

Series from October91
MAX038 based function generator May 95
MAX 038 based 0.1 Hz to 20MHz July 96

Very low cost December 98

 

Beware the original data sheet for the 8038. Intersil produced a more realistic "update" in 1996, which implicitly admitted that the original was not completely accurate. I think the 1996 update was titled "Everything you wanted to know about the 8038" - or something like that. I think they then re-issued a later version early in the 2000's.

 

You might want to check this link - someone currently wanting to find a home for an 8038 -

http://www.diyaudio.com/forums/swap-meet/235623-icl8038-waveform-generator-any-interest.html

 

Hi Dr. killjoy,

Strangely enough I've just built a function generator based on the ICL 8038, at least breadboarded it out.... It works really well, just some minor issues to iron out. Rather than hijack this thread I'll start a new one ;-)

I built #1 the Velleman version and its rubbish, the Dave Jones version is probably quite good, but the chip is exxxxxxpensive, the last one just doesn't hack it really.

Anyway, I've got a spare ICL 8038 chip, PM me your address and I'll stick it the post tomorrow! If you want that is. I used this design here.

All the best Steve.

I would like to take you up on the offer but right now I can't pm you for some reason ????

 

OK, looks like the default setting is to deny PM's... I've just changed it to allow them, maybe you could try again?

<USER CP> <settings and options> <edit options>

 

Take a look at this chip http://www.exar.com/communications/timing/voltage-controlled-oscillator-vco/xr2209 Both xr2206 and MAX038 is obsolete, and high prized. But the xr2209 is still active. If you in the link I provided click on buy now. You will find out who is stocking this chip

Nice chip. If asked I would have said it was obsolete!!

 

It's on it's way courtesy of Royal Mail, about 4-5 working days to the US of A.....
Enjoy.

Steve.

 

Steve, that's very kind of you to contribute.
Thanks for promoting the concept of the Gift Economy.

http://www.guardian.co.uk/commentisfree/video/2012/jul/30/charles-eisenstein-gift-economy

 

@ MrChips....

Not sure I was trying to promote anything really, however I have a great dislike for waste of any kind. I can't remember whether I purchased the chips as a '2 for' or given my propensity for creating the magic smoke, as an insurance policy. It's not important because I would rather have someone get the use of it than have it sit in my parts box looking pretty!

I must say I thought the link you posted was interesting... I do believe there is something to be said for sharing, which is why we all participate in forums (fora?) such as this.

All the best Steve.