I'm sorry I was mistaken, a 555 will not produce a triangle wave. I was looking at the datasheet, and on a graph, I saw a triangle wave, but didn't realize that it was actually the RC network charging and discharging.

BUT, I see no reason why you couldn't use the RC network as an output. Of course it wouldn't be a perfect triangle wave, as a capacitor charges very fast at first, then slower. It would also have to be buffered, as any load would change the value of the RC network.

Or I'm sure there's an easy way of taking the square wave output of the 555 and changing it to a triangle wave. Whichever is less complicated.

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I'm no electronics god, i just talk too much.

 

You could use an opamp as an integrator to convert a square wave to a triangle wave. Then you don't even need a 555 as an oscillator, just use an opamp as a Schmitt trigger with positive feedback from the output of the integrator.

Attached Images

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Uncle $crooge

 

MAX038 do everything

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Steve

 

Digikey doesn't have any MAX038's. When they get some it sells for more than $23.00US.

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Uncle $crooge

 

I will use a 555 to generate a 50% duty cycl at a variable frequenct, this output will then be put through an intergrator and then do through a series of op amps and comparators to acheve a variable duty cycle, wariable frequency square waves for conttroling the gate drivers, I'll post a block diagram soon (once I've completed it)

the specs on the coils, it will be a table top unit with a goal of 200w

a small 3 by 18 inch secongaty with a small topload

the mosfets have 2ot yet been chosen nore have the gate drivers been designed yet
I'll probably go for 400v 10a n mosfets
I'm just designing the electronic control first it will probably be used on multiple coils

It is just a normal sstc using a h-bridge to double the voltage swing, it is not a drsstc because there is no tank capacitor

 

the beauty with mAX038 is that you don't have to care about the filtering. If you use a double integrator, you'll have big loss if you don't play with the R or C values.

Sure they are a bit expensive but they work good. Probably the best solution if some wants to do a bench Freq Generator.

EDIT: mmm seems i need an update... oups..
forget me... i'll maybe in the deep shXX one day. i have thousands of those on the market now.. ARRGH! No i'm not going to sold the 500 i still have in stock...

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Steve

 

I have a Wien Bridge sine-wave generator whose amplitude bounces and bounces and bounces and ... whenever its frequency is changed.

I also have a phase-shift sine-wave generator that is tuned with a 3-stage pot.

I also have a very low distortion sine-wave generator that makes a fundamental with 10 digital steps and is smoothed with a pair of switched-capacitor lowpass filter ICs.

I used to have a sine-wave generator that made a crappy sine-wave out of a triangle wave using an ICL8038 IC.

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Uncle $crooge

 

Ok guys thanks for all the help I'll use a dual op amp setup ag audioguru suggersted, one op amp to generate a square wave, the other as an integrator

it will be like this

 

Hello,

very much a newbie at building electronic circuits.

I have some op-amps (386 and 741)

trying to make a triangle wave.

this schematic looks nice, though I am not sure what pins to use or which parts are represent.

any help available?

I do realize this thread is now a couple years old.

thanks in advance

 

An LM386 is a small power amplifier, not an opamp.
A lousy old (40 years old) 741 opamp has trouble above only 9kHzand is noisy. Better opamps go well up to 100kHz and are low noise.

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Uncle $crooge

 

okay, but these are what I have to work with, is there any sort of tri or sine wave I could make wth these chips?

 

You can make a low frequency triangle-wave with two 741 opamps.
The datasheet of the LM386 shows how to make a Wien Bridge sine-wave oscillator with a light bulb to stabilize the amplitude.

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Uncle $crooge

 

is there a schematic available for this low frequency triangle wave oscillator?


thanks much.

 

5 or 6 posts above this post.

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Uncle $crooge

 

right, but as my original post in this thread stated, I am not sure which pins this schematic is referring to on the chip.

I am assuming the - represents pin 2 and the + pin 3? what pin is represented by the output? what type of caps and resistors hould I be using?