^ unless you are plugging in a value like 2 ohms for ESR 😛 according to the formula a 10,000 uF cap has an impedance of around 0.01 ohms at 100Hz.... the ESR of a good 10,000uF cap will be around 0.05 ohms. so plugging in 2 ohms as per the original post surely does make a difference!! (it certainly does in spice!!)
Obviously with smaller caps and low frequencies the impedance due to reactance will dominate. Sorry just butting in because I'm learning from this too 🙂 I have a vague idea of how things work but tend to gloss over the actual theory (especially when it involves equations) 🙄
Tony.
Obviously with smaller caps and low frequencies the impedance due to reactance will dominate. Sorry just butting in because I'm learning from this too 🙂 I have a vague idea of how things work but tend to gloss over the actual theory (especially when it involves equations) 🙄
Tony.
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Here's where practice intrudes- in a high voltage circuit, you're unlikely to find 1,000u, much less 10,000u! 😀 In the C1 position, you'd arc the rectifiers. In the C2 position, the sheer size and the ESR will probably not have a major effect because of the choke.
In any case, once the O/P is confident in his ability to do the basic calculations, the right numbers can be plugged into the sim.
In any case, once the O/P is confident in his ability to do the basic calculations, the right numbers can be plugged into the sim.
Excellent, you're getting a general feel for the numbers! Now, how do those numbers change with 2 ohms of ESR? Remember to use the right formula...
At the 60hz level adding the ESR increased the impedance by .015 ohms, which is nothing really added to 132 ohm
At the 960hz level adding the ESR increased the impedance by 8.54 ohms, which is more than doubling the impedance since it started out at 8.3 ohms, and making a total of 16.84 ohms.
At the 960hz level adding the ESR increased the impedance by 8.54 ohms, which is more than doubling the impedance since it started out at 8.3 ohms, and making a total of 16.84 ohms.
Should have said equating the ESR raised the impedance by .23 ohms.
Just noticed that someone gave this thread a 1 star rating. Is this that dumb of a question???
Just noticed that someone gave this thread a 1 star rating. Is this that dumb of a question???
OK, so now you've spotted something important- the capacitive impedance is infinite at DC, drops proportionately with frequency, and has the ESR as an asymptote. You also understand that for small caps (like 20u), the ESR is not going to be a big contributor- in your sim, you can see this by varying it from 0.1 ohm to 2 ohms and seeing the difference in the output voltage and ripple.
Now there's one more complication that you'll need to learn about (equivalent series inductance), but that's not a big issue at the low frequencies you're working with, and you can put that off for another day.
Now there's one more complication that you'll need to learn about (equivalent series inductance), but that's not a big issue at the low frequencies you're working with, and you can put that off for another day.
Yes they will swamp it as far as values go; but they are in different parts of the circuit thus have different impacts. You can't disregard cap ESR because of transformer or diode ESR.
Jan
Not ignoring it, just that it's not so important in this case since the end use is a guitar amp not hi-fi, but your point is well taken 😀
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