Ohh ok cool, I have forgotten about the -12 supply because my 555 Oscillator doesn’t use a -12 supply, it only uses a +12 and a Ground.
You see on my scope, I saw this weird half and reversed square wave and sine wave thing and didn’t understand that one so well.
1.jpg - output from the op-amp without a negative supply
2.jpg – output from the op-amp without a negative supply and a cap to the output and ground connected
You see on my scope, I saw this weird half and reversed square wave and sine wave thing and didn’t understand that one so well.
1.jpg - output from the op-amp without a negative supply
2.jpg – output from the op-amp without a negative supply and a cap to the output and ground connected
yeah, it's only working on half the signal.
I would power the 555 from both rails, ignore neutral (just for the 555), capacitor couple to the op amp, and proceed with the op amp as shown in the second op amp circuitry in the article.
What value for the cap? 0.1 microfarad or larger should work fine; frankly, you're at such a low voltage you could just try different caps and see which one works OK. A little rounding of the square wave probably wouldn't hurt anything anyway.
Or you could couple with a transformer, a tiny signal tx if you have one.
or you could bag the 555 and build the whole circuit with op amps as shown in the article.
best, charles
I would power the 555 from both rails, ignore neutral (just for the 555), capacitor couple to the op amp, and proceed with the op amp as shown in the second op amp circuitry in the article.
What value for the cap? 0.1 microfarad or larger should work fine; frankly, you're at such a low voltage you could just try different caps and see which one works OK. A little rounding of the square wave probably wouldn't hurt anything anyway.
Or you could couple with a transformer, a tiny signal tx if you have one.
or you could bag the 555 and build the whole circuit with op amps as shown in the article.
best, charles
I’ve got my Negative supply working now it’s +-7v something, but my op-amp aint doing a thing. It only invert the signal if I use the invert pin on the chip, but all that caps and resistors is making no difference on the output signal wave then using in the op-amp circuit. I tried a battery for the negative supply it’s the same as then using my negative supply.
I’m using my 555 oscillator to make my square wave and to supply my negative supply, it’s very stable then using together, so this combination it’s like doing two posies with one Johnnie.
So I don’t know how to fix this one. I’m getting the idea the 714 op-amp wants to work different than the LMH6622
I’m using my 555 oscillator to make my square wave and to supply my negative supply, it’s very stable then using together, so this combination it’s like doing two posies with one Johnnie.
So I don’t know how to fix this one. I’m getting the idea the 714 op-amp wants to work different than the LMH6622
are you still using the 555 for the power supply?
i think your problem is the power supply and your ground not being a true neutral return.
the type of op amp should make absolutely no difference, as long as the pin-out is the same. especially for this application.
i would strongly suggest you just hook up two batteries in series, so you have 12 V positive, 12 V negative, and ground (return) where the two batteries hook together. the problem right now is you don't know if the problem is the power supply or the circuit or the op amps.
then put the circuit together using two op amps as shown, and be sure, where the schematic is showing things to ground, that you're using the neutral return for ground, not the negative rail.
now, the two power supply pins on each op amp go the two rails, to the 12 V positive rail and the 12 V negative rail. this is so the sine wave can go both positive and negative relative to ground (neutral return). But the other components, where it shows them grounded, the ground is not the negative rail but instead the return, where the two batteries are hooked together.
you have to go back to square one, to a power supply that you KNOW is working correctly, and then work your way back.
by the way, the circuit as shown is for a radio frequency, I forget what, but I would go ahead and just set the circuit up as shown, using the two batteries in series for the power supply (+ and - rails) and neutral return for the ground, get it working, and then worry about modifying it to get the frequency down to 50 Hz. I don't htink the values of the components for the square to sine conversion part of the circuit, the second op amp, change for different frequencies, but maybe they do...check the article; it should say in there whether they have to change if the frequency changes.
I will go ahead and look for a different circuit that is already set up for 50 Hz, but this one really should work. And, for low frequency stuff, an op amp is an op amp is an op amp, it matters not which one you use, as long as the pins are the same. Trust me on this one.
Now, the op amp you're using, it can take 24 V, + and - 12 V, right? maybe you're using a 5 volt only op amp, in which case it's already blown. But, I'm just guessing, I don't actually know if there are any op amps that work only at 5 V.
oh well, back to the drawing board. if anybody out there on this forum actually knows what op amp and what circuit to use, please feel free to help us out, I'm no expert on this, I'm just trying to help out, and apparently not doing a very good job either.
best, charles
i think your problem is the power supply and your ground not being a true neutral return.
the type of op amp should make absolutely no difference, as long as the pin-out is the same. especially for this application.
i would strongly suggest you just hook up two batteries in series, so you have 12 V positive, 12 V negative, and ground (return) where the two batteries hook together. the problem right now is you don't know if the problem is the power supply or the circuit or the op amps.
then put the circuit together using two op amps as shown, and be sure, where the schematic is showing things to ground, that you're using the neutral return for ground, not the negative rail.
now, the two power supply pins on each op amp go the two rails, to the 12 V positive rail and the 12 V negative rail. this is so the sine wave can go both positive and negative relative to ground (neutral return). But the other components, where it shows them grounded, the ground is not the negative rail but instead the return, where the two batteries are hooked together.
you have to go back to square one, to a power supply that you KNOW is working correctly, and then work your way back.
by the way, the circuit as shown is for a radio frequency, I forget what, but I would go ahead and just set the circuit up as shown, using the two batteries in series for the power supply (+ and - rails) and neutral return for the ground, get it working, and then worry about modifying it to get the frequency down to 50 Hz. I don't htink the values of the components for the square to sine conversion part of the circuit, the second op amp, change for different frequencies, but maybe they do...check the article; it should say in there whether they have to change if the frequency changes.
I will go ahead and look for a different circuit that is already set up for 50 Hz, but this one really should work. And, for low frequency stuff, an op amp is an op amp is an op amp, it matters not which one you use, as long as the pins are the same. Trust me on this one.
Now, the op amp you're using, it can take 24 V, + and - 12 V, right? maybe you're using a 5 volt only op amp, in which case it's already blown. But, I'm just guessing, I don't actually know if there are any op amps that work only at 5 V.
oh well, back to the drawing board. if anybody out there on this forum actually knows what op amp and what circuit to use, please feel free to help us out, I'm no expert on this, I'm just trying to help out, and apparently not doing a very good job either.
best, charles
Here's a different article and a different circuit. For crissakes, I'm sure this one works, although I continue to suspect your problem is your power supply, Jacquesl.
A very nice feature of this circuit is it needs only a positive rail and ground, it doesn't need two rails plus neutral. It can run off 12 V or 24 V. Also, the author gives the equation for determining the frequency, and it's pretty straight-forward.
Twin-T Audio Sine Wave Oscillator
This circuit produces a clean sine wave signal ideal for audio testing, or wherever a good-quality sine voltage source is required. It uses only one integrated circuit which is a common dual operational amplifier, the Texas Instruments TL072CP. The values shown provide an output frequency of about 1000 Hertz. This frequency may be varied over a wide range, using the formula shown in the schematic. For most audio frequencies, the oscillation rate is almost exclusively determined by the twin-T network in U1A's feedback loop, provided that the gain-bandwidth product and slew rate specifications for the op amp are sufficiently high. For frequencies exceeding 10kHz, an faster op-amp in the U1A position is recommended.
The ratios of the resistors and capacitors in the twin-T network must be accurate to ensure oscillation. For that reason, ±1% components are indicated. The resistors in the twin-T network should be metal film, and the capacitors mica (best), polystyrene (good), or C0G ceramic (sufficient). Polyester capacitors may be used for economy if large C1, C2, and C3 values, such as those exceeding 10,000pF, are required. Note that the capacitor ratio of 2:1 is most conveniently obtained with the standard values that have this nominal relationship, e.g., 750pF and 1500pF, as shown in the schematic. Other useful combinations include 1000pF and 2000pF, 1100pF and 2200pF, 1500pF and 3000pF, and 1800 and 3600pF. Alternatively, four equivalent capacitors may be used, with two of them paralleled to make C1. This technique has the advantage that capacitors from the same lot are more likely to be closer in value. The same technique is also applicable for the three resistors, especially when an exact 2:1 ratio of resistance values is not available.
Operation of this oscillator is unconventional, in that the frequency-selective network is in the negative feedback path of the operational amplifier. The positive feedback required for oscillation is provided by R4. Transistor Q1 is part of an automatic gain control (AGC) servo that regulates the positive feedback to keep the sine wave output at a consistent amplitude.
With transistor Q1 and resistor R4 omitted, U1A's transfer function from its positive input to output is a notch filter with a frequency and depth determined by the twin-T component values. The addition of Q1 and R4 provides U1A positive feedback with zero degrees of phase shift at the notch frequency. The circuit will therefore oscillate at this frequency when Q1's emitter-to-collector resistance (Rec) is such that:
(R4 + Rec) / Rec (expressed in dB) =
U1A's open-loop gain (expressed in dB) -
the magnitude of the notch depth (expressed in dB)
U1B and its associated components complete the AGC servo. The series-connected diodes provide negative peak-level detection of the sine wave voltage and also determine the amplitude of the output. Q1 is operated close to maximum conduction, so the small voltage from its emitter to collector contributes negligible distortion to the sine wave. The 0.1uF integrating capacitor in U1B's feedback path was chosen to provide adequate AGC-loop stability for the selected oscillation frequency. The 10K resistor in parallel with Q1 ensures start-up.
The oscillator's amplitude, as well as frequency, is essentially independent of the power supply voltage. An output amplitude of 1.6 volts, peak-to-peak, was chosen to accommodate power supply voltages as low as 6 volts. Replacing the TL072CP with a rail-to-rail dual operational amplifier such as the Analog Devices type AD823AN will permit operation from even lower supply voltages, such as 4 volts. The oscillator will operate conveniently from a single 9-volt battery, and consumes less than 5 milliamperes of current when using the TL072CP. The 470 ohm resistor in the output prevents instabilities from capacitive loads such as long cables, and the 1uF capacitor removes the DC term at U1A. The output's 100K resistor discharges the 1uF capacitor to prevent voltage transients when connecting a load.
Acknowledgement
The author gratefully acknowledges Rick Hansen for providing an analysis of this circuit's operation.
April 12, 2001
Text and images ©2001 by Arthur Harrison
P.S.: another circuit to follow. IMPORTANT NOTE: this circuit could be powered by 24 volts, from the positve and negative rails, and then we could design the rest of the inverter to not need the return, or we could use the return in the rest of the circuit but not need it for this part.
best, charles
A very nice feature of this circuit is it needs only a positive rail and ground, it doesn't need two rails plus neutral. It can run off 12 V or 24 V. Also, the author gives the equation for determining the frequency, and it's pretty straight-forward.
Twin-T Audio Sine Wave Oscillator
This circuit produces a clean sine wave signal ideal for audio testing, or wherever a good-quality sine voltage source is required. It uses only one integrated circuit which is a common dual operational amplifier, the Texas Instruments TL072CP. The values shown provide an output frequency of about 1000 Hertz. This frequency may be varied over a wide range, using the formula shown in the schematic. For most audio frequencies, the oscillation rate is almost exclusively determined by the twin-T network in U1A's feedback loop, provided that the gain-bandwidth product and slew rate specifications for the op amp are sufficiently high. For frequencies exceeding 10kHz, an faster op-amp in the U1A position is recommended.
The ratios of the resistors and capacitors in the twin-T network must be accurate to ensure oscillation. For that reason, ±1% components are indicated. The resistors in the twin-T network should be metal film, and the capacitors mica (best), polystyrene (good), or C0G ceramic (sufficient). Polyester capacitors may be used for economy if large C1, C2, and C3 values, such as those exceeding 10,000pF, are required. Note that the capacitor ratio of 2:1 is most conveniently obtained with the standard values that have this nominal relationship, e.g., 750pF and 1500pF, as shown in the schematic. Other useful combinations include 1000pF and 2000pF, 1100pF and 2200pF, 1500pF and 3000pF, and 1800 and 3600pF. Alternatively, four equivalent capacitors may be used, with two of them paralleled to make C1. This technique has the advantage that capacitors from the same lot are more likely to be closer in value. The same technique is also applicable for the three resistors, especially when an exact 2:1 ratio of resistance values is not available.
Operation of this oscillator is unconventional, in that the frequency-selective network is in the negative feedback path of the operational amplifier. The positive feedback required for oscillation is provided by R4. Transistor Q1 is part of an automatic gain control (AGC) servo that regulates the positive feedback to keep the sine wave output at a consistent amplitude.
With transistor Q1 and resistor R4 omitted, U1A's transfer function from its positive input to output is a notch filter with a frequency and depth determined by the twin-T component values. The addition of Q1 and R4 provides U1A positive feedback with zero degrees of phase shift at the notch frequency. The circuit will therefore oscillate at this frequency when Q1's emitter-to-collector resistance (Rec) is such that:
(R4 + Rec) / Rec (expressed in dB) =
U1A's open-loop gain (expressed in dB) -
the magnitude of the notch depth (expressed in dB)
U1B and its associated components complete the AGC servo. The series-connected diodes provide negative peak-level detection of the sine wave voltage and also determine the amplitude of the output. Q1 is operated close to maximum conduction, so the small voltage from its emitter to collector contributes negligible distortion to the sine wave. The 0.1uF integrating capacitor in U1B's feedback path was chosen to provide adequate AGC-loop stability for the selected oscillation frequency. The 10K resistor in parallel with Q1 ensures start-up.
The oscillator's amplitude, as well as frequency, is essentially independent of the power supply voltage. An output amplitude of 1.6 volts, peak-to-peak, was chosen to accommodate power supply voltages as low as 6 volts. Replacing the TL072CP with a rail-to-rail dual operational amplifier such as the Analog Devices type AD823AN will permit operation from even lower supply voltages, such as 4 volts. The oscillator will operate conveniently from a single 9-volt battery, and consumes less than 5 milliamperes of current when using the TL072CP. The 470 ohm resistor in the output prevents instabilities from capacitive loads such as long cables, and the 1uF capacitor removes the DC term at U1A. The output's 100K resistor discharges the 1uF capacitor to prevent voltage transients when connecting a load.
Acknowledgement
The author gratefully acknowledges Rick Hansen for providing an analysis of this circuit's operation.
April 12, 2001
Text and images ©2001 by Arthur Harrison
P.S.: another circuit to follow. IMPORTANT NOTE: this circuit could be powered by 24 volts, from the positve and negative rails, and then we could design the rest of the inverter to not need the return, or we could use the return in the rest of the circuit but not need it for this part.
best, charles
My op-amps is not responding in any way, it doesn’t even seem to be connected if using it.
This is not going to work, the LMH6622 have two Inputs Input A and input B and no other stuff so by using a 741 op-amp that only have one input and some weird pins that I have no idea what to do with. Offset null 1 and Offset null 2 is probably not going to work on the same principle, so I’m a bit confused about this stuff it’s not working like it should. I have no idea how to use the Offset null pins on the chip
This is not going to work, the LMH6622 have two Inputs Input A and input B and no other stuff so by using a 741 op-amp that only have one input and some weird pins that I have no idea what to do with. Offset null 1 and Offset null 2 is probably not going to work on the same principle, so I’m a bit confused about this stuff it’s not working like it should. I have no idea how to use the Offset null pins on the chip
Attachments
jacquesl said:
Don't connect them, offset trim is optional. (If you needed to, you'd add a 10k trimpot, connect both ends to the offset pins and the wiper to positive supply).
Note the 741 is a SINGLE opamp, the LMH6622 is double = two opamps on one chip. You need TWO 741s. One of them will be amp A, the other B. The 6622's pins 3,2 and 1 correspond to 3, 2 and 6 on amp A; pins 5, 6 and 7 to 3, 2 and 6 on amp B. Positive supply goes to pin 7 on amp A and B, negative or ground to pin 4.
Yea I understand that, but I want to use the 741 op-amp to convert my square wave to a sine wave, but having some difficulties with that task, do you know to fix that one wine&dine ?
Jacquesl,
when you run into problems with an electronic circuit, the best way, I have found, to get it straightened out is to retreat!
go back to something known, and get that to work.
you would be better off to use two op amps and do the circuit as shown. it should work. once you have it working, wiring it AS SHOWN,
then you can see if you can make a 555 work with a sine shaper op amp circuit, once you've proven to yourself the other circuit works, because now you've succeeded in proving that the power supply, op amps, and other circuit are working properly.
It's a huge help to just step back and start over, working from the known before you try the unknown.
but, if you get the two op amp design to work, then you may not need to get the 555 to work.
by marrying yourself to the 555, you're causing yourself big problems, because you don't have enough electronic knowledge to be able to splice a part of one circuit onto a part of a different circuit. It's not the components fault this isn't working, it's your lack of experience and knowledge. When you lack experience and knowledge, the best way to get it is to start from known work that is already known to work.
What's happening right now, unfortunately, is you're wasting time beating your head against a problem you don't know how to solve. We've supplied you with a way of cutting through the gordion knot - just do the blasted circuit I gave you - if you are not willing to do that, then frankly I doubt anyone here is going to want to waste their time trying to help you be pig-headed.
give up the goddamm 555 and just do the f___g circuit we know will work!!
best, charles
when you run into problems with an electronic circuit, the best way, I have found, to get it straightened out is to retreat!
go back to something known, and get that to work.
you would be better off to use two op amps and do the circuit as shown. it should work. once you have it working, wiring it AS SHOWN,
then you can see if you can make a 555 work with a sine shaper op amp circuit, once you've proven to yourself the other circuit works, because now you've succeeded in proving that the power supply, op amps, and other circuit are working properly.
It's a huge help to just step back and start over, working from the known before you try the unknown.
but, if you get the two op amp design to work, then you may not need to get the 555 to work.
by marrying yourself to the 555, you're causing yourself big problems, because you don't have enough electronic knowledge to be able to splice a part of one circuit onto a part of a different circuit. It's not the components fault this isn't working, it's your lack of experience and knowledge. When you lack experience and knowledge, the best way to get it is to start from known work that is already known to work.
What's happening right now, unfortunately, is you're wasting time beating your head against a problem you don't know how to solve. We've supplied you with a way of cutting through the gordion knot - just do the blasted circuit I gave you - if you are not willing to do that, then frankly I doubt anyone here is going to want to waste their time trying to help you be pig-headed.
give up the goddamm 555 and just do the f___g circuit we know will work!!
best, charles
Ok I’m going to build that one as soon a posible
I’ve founded a cool site :
http://www.faqs.org/docs/electric/Semi/SEMI_8.html
They show a circuit, sine in and square out, it would be nice to swap that option, so how can that be done or is it possible to do that. This op-amp stuff is very new to me, it’s kind of interesting to me.
I’ve founded a cool site :
http://www.faqs.org/docs/electric/Semi/SEMI_8.html
They show a circuit, sine in and square out, it would be nice to swap that option, so how can that be done or is it possible to do that. This op-amp stuff is very new to me, it’s kind of interesting to me.
Jacquesl,
that is a great, great article!
It will give you all the info you need to start running with this thing, good score.
it has a section on hysterisis that we'll be using to see if we can make this power supply free-wheeling, not needing a clock, for the output section.
best, charles
that is a great, great article!
It will give you all the info you need to start running with this thing, good score.
it has a section on hysterisis that we'll be using to see if we can make this power supply free-wheeling, not needing a clock, for the output section.
best, charles
Do you know charles, I haven’t actually seen a circuit diagram on the web using a 714 Op-amp to do this kind of wonder works so I’m thinking I’m using the wrong IC for the impossible purpose.
And the LMH6622 and TL082 is not available in the electronic shops, the only thing I can get is the LM741 Op-amp and the NE555 single timer IC.
I have some various IC’s from all my old 486 motherboards
Here are the following 74LS ranges I’ve got, can I by any change use them to convert the square signal to sine
SN74LS373N
SN74LS04N
SN74LS27N
SN74LS157N
SN74LS175N
SN74LS244N
SN74S280N
SN74LS02N
SN74LS08N
SN74LS245
SN74LS32N
SN74L74N
SN74LS138N
SN74LS10N
SN74LS20N
SN74LS670N
SN74LS244N
SN74LS00N
SN74LS322AN
SN74LS74AN
SN74LS20N
SN74LS14N
SN75188N
M74LS92P
SN75189N
And the LMH6622 and TL082 is not available in the electronic shops, the only thing I can get is the LM741 Op-amp and the NE555 single timer IC.
I have some various IC’s from all my old 486 motherboards
Here are the following 74LS ranges I’ve got, can I by any change use them to convert the square signal to sine
SN74LS373N
SN74LS04N
SN74LS27N
SN74LS157N
SN74LS175N
SN74LS244N
SN74S280N
SN74LS02N
SN74LS08N
SN74LS245
SN74LS32N
SN74L74N
SN74LS138N
SN74LS10N
SN74LS20N
SN74LS670N
SN74LS244N
SN74LS00N
SN74LS322AN
SN74LS74AN
SN74LS20N
SN74LS14N
SN75188N
M74LS92P
SN75189N
Jacques, you can get cheap dual opamps like lm358 from communica, mantech or RS components localy.
Yeah, Jacquesl, I think Nordic is steering you aright....
Good God, sorry, I don't have all that TTL stuff memorized, I don't know if any of those are op amps, they are probably all various other things like comparators and counters and logic gates (AND, OR, NOR, NAND, etc), doubt any of them would do the job at all.
I'm afraid there just isn't a substitute for finding a few op amps....is the real problem you can't afford a few dollar chips? it's no crime to be poor, God knows I know what it's like to not have enough money to go to McDonalds, much less buy an op amp chip.....
best, charles
Good God, sorry, I don't have all that TTL stuff memorized, I don't know if any of those are op amps, they are probably all various other things like comparators and counters and logic gates (AND, OR, NOR, NAND, etc), doubt any of them would do the job at all.
I'm afraid there just isn't a substitute for finding a few op amps....is the real problem you can't afford a few dollar chips? it's no crime to be poor, God knows I know what it's like to not have enough money to go to McDonalds, much less buy an op amp chip.....
best, charles
Yea Nordic I know that places like mantech and yebo eletronics but that’s 3hours in the car from my home. And it’s getting holiday time now, and that stuff, and all the sweat shops probably going to close. So all the odds is against me or something.
Charles, I’ve checked some datasheets out in the 74LS range, but it’s all inverters, smith triggers and gates, I’m also not thinking that it going to work.
Charles, I’ve checked some datasheets out in the 74LS range, but it’s all inverters, smith triggers and gates, I’m also not thinking that it going to work.
Hmmm....well, if you can't order things by mail, I gotta say I'm stumped...I don't know how you could ever complete this, cuz you're gonna need a ton of stuff, like the output device (BJT or MOSFET) and transformers and resistors...yikes, it's gonna be a long list, Jacquesl, and if you go Class D with info from the Class D forum this is going to be a very complicated project, but even my attempt to see if we could do this in a simple way is still gonna require ordering and obtaining parts I'm sure you don't have.
I wish I knew how to help you.
I'm happy to do a search and see if we can get the 555 to be your sine wave generator, but that sure doesn't solve the rest of your components-sourcing problems.
Ideas?
best, charles
I wish I knew how to help you.
I'm happy to do a search and see if we can get the 555 to be your sine wave generator, but that sure doesn't solve the rest of your components-sourcing problems.
Ideas?
best, charles
I had this idea for a week long now, to make this sine wave with a 555 timer and with a inverted op-amp and some transistor to switch the wave if necessary.
Here you can check out some info about the 555 timer stuff:
http://www.uoguelph.ca/~antoon/gadgets/555/555.html
My crazy idea no.1: To take the 555 timer and to make the wave curve by putting a capacitor in the circuit like described in the link, and use the last negative curve and invert the signal to positive my using the 741 op-amp invert function or an inverted transistor circuit, and then to use the positive curve to flip the entire signal to negative again. So the 555 timer will control your timing and will create your signal flip-flop reference signal for the positive curve fade in and fade out and will reset the thing to negative again. So this will probably need some homemade SRC’s to operate at the activation and reset of the wave. Yea and another thing you can use your 555 to generate your negative power supply, you will only need to adjust the frequency if needed.
I know this crazy idea no.1 will be some major stupid design and time wasting, but I think you might not disagree with me that this might be interesting, how it all works.
Here you can check out some info about the 555 timer stuff:
http://www.uoguelph.ca/~antoon/gadgets/555/555.html
My crazy idea no.1: To take the 555 timer and to make the wave curve by putting a capacitor in the circuit like described in the link, and use the last negative curve and invert the signal to positive my using the 741 op-amp invert function or an inverted transistor circuit, and then to use the positive curve to flip the entire signal to negative again. So the 555 timer will control your timing and will create your signal flip-flop reference signal for the positive curve fade in and fade out and will reset the thing to negative again. So this will probably need some homemade SRC’s to operate at the activation and reset of the wave. Yea and another thing you can use your 555 to generate your negative power supply, you will only need to adjust the frequency if needed.
I know this crazy idea no.1 will be some major stupid design and time wasting, but I think you might not disagree with me that this might be interesting, how it all works.
Attachments
Lol Jacques, I thought it says Cape Town under your location...
Where are you based...?
PS, RS will ship to your door.
Playing around like that is usefull even if it is just for learning why something won't work.
Also you could order opamp samples from texas instruments at no cost, they send it with 2day express mail. I was impressed as heck, only used that service for the first time a week or so ago...
Where are you based...?
PS, RS will ship to your door.
Playing around like that is usefull even if it is just for learning why something won't work.
Also you could order opamp samples from texas instruments at no cost, they send it with 2day express mail. I was impressed as heck, only used that service for the first time a week or so ago...
Nordic, dude, great information, thanks.
Yeah, exactly, I have found it really is useful to learn how things don't work the way one might hope they would work, learning time well spent.
And, sometimes, one gets lucky and finds a simple way to get something done.
I remember years ago I wanted to do a particular thing with an op amp; at a conference I mentioned it to some op amp experts, who told me it wouldn't work, and proved it mathematically.
I went home and started messing around, and got it to work. Now, it didn't work perfectly, it wasn't mathematically perfect, but I did achieve an acceptable approximation of what I needed.
To be fair to the engineers, I didn't say to them: "is there an inaccurate way to do such and such that would still work well enough?", perhaps thye might (or might not!) have given me a different answer.
The same applies to this project. Certainly, the right way to do this thing would be a Class D amp - but I am very hopeful we can figure out a simple, admittedly half-assed, way to get an approximation of a sine wave for the power out that will suffice. It would be a huge gain to have a power sine wave generator that is simple, relatively cheap, and while not perfect, good enough to get the job done.
best, charles
Yeah, exactly, I have found it really is useful to learn how things don't work the way one might hope they would work, learning time well spent.
And, sometimes, one gets lucky and finds a simple way to get something done.
I remember years ago I wanted to do a particular thing with an op amp; at a conference I mentioned it to some op amp experts, who told me it wouldn't work, and proved it mathematically.
I went home and started messing around, and got it to work. Now, it didn't work perfectly, it wasn't mathematically perfect, but I did achieve an acceptable approximation of what I needed.
To be fair to the engineers, I didn't say to them: "is there an inaccurate way to do such and such that would still work well enough?", perhaps thye might (or might not!) have given me a different answer.
The same applies to this project. Certainly, the right way to do this thing would be a Class D amp - but I am very hopeful we can figure out a simple, admittedly half-assed, way to get an approximation of a sine wave for the power out that will suffice. It would be a huge gain to have a power sine wave generator that is simple, relatively cheap, and while not perfect, good enough to get the job done.
best, charles
Jacquesl, very interesting indeed; I don't havfe time right now, but will later today; if anyone else has input, you're welcome to chime in!
best, charles
best, charles
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