Looking for a tested function generator circuit please?

danadak

Joined Mar 10, 2018
4,057
Do you have desired specifications ? Output frequency, types of waveforms,
how you want to control it, output power levels, accuracy, environmental temp-
erature......

Regards, Dana.
 

recklessrog

Joined May 23, 2013
985
If you are not in a hurry, I have a schematic of a function generator members of my club have built that with a few minor mods will produce sine, square and triangular waveforms from 0.1 to 100kHz. It performs well and is in constant use. I cannot remember where they originally got the schematic, probably from an article in a magazine from the library that Bertus has.
I am away from home until early next week, but if you can wait that long, I will dig it out and post it on here.
Maybe if Bertus reads this, he may know where to find it quicker than me.
 

Thread Starter

DrewStupid

Joined Nov 28, 2018
64
If you are not in a hurry, I have a schematic of a function generator members of my club have built that with a few minor mods will produce sine, square and triangular waveforms from 0.1 to 100kHz. It performs well and is in constant use. I cannot remember where they originally got the schematic, probably from an article in a magazine from the library that Bertus has.
I am away from home until early next week, but if you can wait that long, I will dig it out and post it on here.
Maybe if Bertus reads this, he may know where to find it quicker than me.
That would be great !
 

Thread Starter

DrewStupid

Joined Nov 28, 2018
64

recklessrog

Joined May 23, 2013
985
Here is the schematic of the function generator that members of my club built, I think they downloaded it from google but it was a couple of years ago so I'm not sure.
As shown with 741 i.c's, it is only good to 10kHz. If you were to use CA3140's or NE 5534's then they will work well up to 100kHz or better. Possibly TL071 or TL081's would also work.
All the small signal diodes are 1n4148 or 914's. The transistors are not critical either, most small signal complementary pairs will work well. Build it with what you have and see how it performs which is what our club did using mainly salvaged components from scrap circuit boards. Try to get the two attenuator resistor values close to those shown by using series/ parallel combinations if you don't have the exact ones.
To get the next high frequency range 10-100kHz, make SW1 a 5 way to select a 0.47nF capacitor.
Let me know if this is any use to you.
 

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Fluxor1964

Joined Jun 11, 2015
182
If anyone is still looking for a circuit I just found this online and built it on breadboard....bloody brilliant....superb sinewave and all I ever needed....well chuffed!!!

downside is that it is fixed frequency, all I need to do is add an attenuator to give me adjustable output amplitude and job sorted....

I used an LM3403 and a single 9v supply.

Ignore the yellow lines, that was just reference for me when I was checking connections since it didn't work when I first powered up, as usual I had missed a connection.
 

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Thread Starter

DrewStupid

Joined Nov 28, 2018
64
Here is the schematic of the function generator that members of my club built, I think they downloaded it from google but it was a couple of years ago so I'm not sure.
As shown with 741 i.c's, it is only good to 10kHz. If you were to use CA3140's or NE 5534's then they will work well up to 100kHz or better. Possibly TL071 or TL081's would also work.
All the small signal diodes are 1n4148 or 914's. The transistors are not critical either, most small signal complementary pairs will work well. Build it with what you have and see how it performs which is what our club did using mainly salvaged components from scrap circuit boards. Try to get the two attenuator resistor values close to those shown by using series/ parallel combinations if you don't have the exact ones.
To get the next high frequency range 10-100kHz, make SW1 a 5 way to select a 0.47nF capacitor.
Let me know if this is any use to you.
Going to try it ! Thanks.
 
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