Electronics > Beginners
Real World Use Of A Function Generator
rstofer:
Function generators are of some use in education. You really don't 'get' AC impedance until you play with it on the bench. A signal generator, a resistor and capacitor along with a DMM and perhaps a scope really add to the learning. Use the DMM for attenuation and the scope for phase shift.
I remember this exercise from a Circuits Lab I took back in college ('74?) and I still demonstrate it to my grandson and will again when he gets to his Circuits course in a year or so.
Or, maybe you are playing with RC servos and you want a precise pulse width at a 50 Hz rate. That's pretty easy to set up on a function generator.
Or, provide a square wave to an RC circuit and watch the charge and discharge time on a scope. Nothing like nailing those two equations down to a picture.
I got along without an AWG for a very long time. One way or another, I was always able to come up with a signal source. It was usually pretty easy because I didn't do any analog work, just digital. Now that I have an AWG, I can use it for a lot of things that were either awkward or not possible without it.
I don't think it is the first or second item on a bench but if education is part of the deal, a signal source is pretty handy to have.
bob91343:
Interesting idea, a lookup table and a counter. Not sure how to implement it but theoretically it seems easy.
Yet, I would rather do it analog than digital.
If I had a staircase generator I could cobble up a transistor curve tracer. Each step would provide an increment of base current while I would sweep the collector voltage. Or vice versa.
I did build such a curve tracer back in the 1970s and used it to characterize transistors. I thought it might be fun to do it with tubes, but never went that far.
Actually, I see no particular value in a curve tracer other than educational. I suppose one could match transistors that way but any circuit requiring matching seems to me poorly designed.
I think I am going off topic here so I apologize.
rstofer:
--- Quote from: bob91343 on April 26, 2019, 10:10:11 pm ---Interesting idea, a lookup table and a counter. Not sure how to implement it but theoretically it seems easy.
--- End quote ---
Depending on the number of samples in the waveform and the required resolution, it can be as simple as a 256x8 bit PROM (or RAM) with a counter. Or it can be done with internal memory from an Arduino.
When you get the 8 bits output, you just run them into an R-2R DAC and you have an analog voltage.
https://www.tek.com/blog/tutorial-digital-analog-conversion-r-2r-dac
I'm not sure how to do it but I'll bet it can be done with a PC sound system.
bob91343:
Well that's the digital way. Any ideas on doing it analog?
I pulled one of my 'extra' function generators out of the closet and I see it has a VCO jack on the back. I must check the other two and see how I can make them play together.
I have no use for this. It's a hobby and just seeing what can be done is an end in itself. I love playing with a TDR, for instance. I can measure coaxial length and impedance, then measure how far it is from my ham rig to the antenna terminals up on the tower. And knowing that, as well as the transmission line impedance, I can calculate the antenna impedance at the antenna. Then I can compare with a Smith chart on a VNA. Results should also agree with using a return loss bridge.
So all of this shakes down to a perhaps perverse joy in owning a good electronics work bench. The OP is to be commended for wanting good gear, although he may need to do some study to learn how to use it all properly. As a matter of fact, probably all of us do, unless Fred Terman is secretly reading this.
When I compare three voltmeters and they all read almost exactly the same, I smile in satisfaction.
Mechatrommer:
--- Quote from: cdev on February 06, 2019, 06:18:36 am ---
--- End quote ---
yay gol yay!
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