Activity for a concerned citizen‭

Type	On...	Excerpt	Status	Date
Answer	—	A: Deriving resistor values for a taper pad attenuator > Yeah, that looks like it's going to be messy. I agree with Olin: the problem starts with three variables and three conditions so, no matter how you look at it, you will end up with a system of equations. However, you can take certain shortcuts (using your 1st picture): $$\begin{align} R{... (more)	—	over 1 year ago
Answer	—	A: Design high -pass filter with 2 points of the bode plot You still haven't said why you need, or even what order, type, etc. Assuming it's a 2nd order, an exact solution involves creating a generic transfer function and then solving a system of equations with imposed conditions (use squared to get rid of radical): $$\begin{align} H(s)&=\dfrac{s^2}{s^2+... (more)	—	over 1 year ago
Answer	—	A: Results of analysis of Hartley oscillator dont make sense If you are pursuing engineering then you can't use doodles instead of schematics generated by dedicated (or not) programs. It will take you just the same amount of time, if not less, and the results would be clear for anyone seeing them. The basic schematic of the Hartley oscillator can be simplif... (more)	—	almost 2 years ago
Answer	—	A: Modelling tunnel diode relaxation oscillator Unless you know the exact formula for the I-V curve, you will never find out anything analytically. Fair warning: very unlikely you will get such formula, since they are strongly non-linear in nature. The analysis of such oscillators is done based on approximations (see the Esaki diode, for example),... (more)	—	almost 2 years ago
Answer	—	A: Complex frequency of a pole This is mostly another view on @Olin's answer. > For different input signals the frequency of the pole will have different values ,the pole as a pole exists for some specific values of L,C s but the frequency of the pole changes. The poles of an LTI system do not change. Since you're giving an ... (more)	—	almost 2 years ago
Answer	—	A: Effect of adding stages to a filter It depends on whther the stages are buffered, or not. If they are buffered then it's more simple, because an RC lowpass has the transfer function: $$H1(s)=\dfrac{\dfrac{1}{RC}}{s+\dfrac{1}{RC}}=\dfrac{1}{sRC+1} \tag{1}$$ And adding $N$ stages will mean $H(s)$ will simply be multiplied $N$ times... (more)	—	almost 2 years ago
Answer	—	A: How to design a low-pass filter when certain conditions must be met Your requirements are odd. Can you specify what purpose that filter is for? I'm saying this because, for a -0.1 dB/Hz, a filter will have a continuously increasing attenuation slope. Think of it like this: at DC, it will have (e.g.) a magnitude of $H(0)=1$. Then, at: $$\begin{align} 1\space\text{... (more)	—	almost 2 years ago
Answer	—	A: Unexpected impedance spike when paralleling capacitors Around the 19 min mark in the video (approximately, found with hovering the cursor over the timeline) you'll see that different capacitors have different values of both capacitances and parasitics, and their combined response causes those peaks. Not lastly, there are PCB traces that come with both th... (more)	—	almost 2 years ago
Answer	—	A: Duty cycle of buck-boost converter If you're referring to this Wikipedia page then the topology has a negative output. In that case, the problem as you have it stated in the OP, is misleading: it should be Vo=-20. With that, extracting D will give: $$D=\dfrac{V{out}}{V{out}-V{in}}=\dfrac{-20}{-20-24}=0.4545$$ Sure enough, a quic... (more)	—	about 2 years ago
Answer	—	A: H(jω) does not exist for unstable systems, but we still use it when designing controllers - contradiction? Please note that the text refers to the integral, or the mathematical evaluation through integration which, indeed, cannot be obtained. But that doesn't mean you can't obtain the Laplace transfer function directly. A hypothetical RLC filter with a negative resistor is very much possible. In fact, it ... (more)	—	over 2 years ago
Answer	—	A: Flyback converter design Try searching for "multiple outputs flyback". Basically, you can't control each, individually, instead you make the voltage feedback as the average between the outputs. Here's a quick'n'dirty test to show what I mean, with a simple voltage mode concoction (don't give it too much thought for the value... (more)	—	over 2 years ago
Answer	—	A: Type II compensation network for a non-ideal transconductance amplifier You can use various methods for it, one way would be to simply use the ideal transfer function and make it in parallel with \$Ro\$: $$\begin{align} A(s)&=R{th}+\dfrac{1}{sC{th}} \tag{1} \\\\ B(s)&=A(s)||C{thp} \\\\ {}&=\dfrac{1}{\dfrac{1}{R{th}+\dfrac{1}{sC{th}}}+sC{thp}} \\\\ {}&=\dfrac{1}{sC... (more)	—	over 2 years ago
Answer	—	A: Critically damped oscillation issue Your derivation is correct, you just missed the sign: \$VL=-VC=2\;\mathrm{V}\$, because the capacitor charges with +2 V, and the discharge accounts for the negative sign on the inductor. The notation of \$VL=-VC\$ may be confusing, so think of it as \$VC=-VL\$, maybe it makes more sense. Verifying... (more)	—	almost 3 years ago
Answer	—	A: Meaning of some components around voltage reference in SMPS `R22, C22, C23`, together with `Rfbt` (feedback top) and `Rfbb` (feedback bottom) form what is called a type II compensator, using TL431 as an opamp with built-in reference. The feedback network is a bit different than what you'd see -- usually it's `R22` series with `C23`, and `C22` in parallel with... (more)	—	almost 3 years ago
Answer	—	A: Moving average that uses less memory? I'm adding this as a corollary to Olin's post, in case an exact formula for attenuation is needed. That basic IIR is derived from the exponential moving average, and its impulse response is: $$h[n]=\alpha x[n]+(1-\alpha)x[n-1]$$ which translates into this transfer function: $$H(z)=\frac{\... (more)	—	over 3 years ago
Answer	—	A: High pass filter design I saw this link by accident and, while Andy's and Olin's answers are spot on, I thought I'd expand a bit on the complications they describe, just so you know what you're missing (or meeting, should you decide to continue). Also, it might get a bit long, but that's why the voting system exists. Fir... (more)	—	over 3 years ago