1. jacopo1919

    Help understanding state variable filter working principle and phase relations

    Hello! I'm looking to the state variable filter proposed from ESP in Project 153 that is a state variable filter that splits the signal in 3 bands and sums them back together. this should give a flat response all over the spectrum when the bands are summed back together. I simulated the circuit...
  2. Younes Thabet

    What type of multi-level input filter is used in a 3-phase 30KW vienna PFC?

    Hello all, I have been checking this 30 kW Vienna PFC rectifier reference design and didn't understand why all of these filters are used for this kind of application, i mean half of the board is inductors and capacitors for the filters. Can someone explain what type of filters are used? and...
  3. jbHardwareDev

    Dual mosfet switch problem

    Hi. I plan to make a pcb that drives peltier and heating pad. Only one of those works at the same time. Load elements are parallel to capacitors. I have very little space on pcb so it would be nice if I could use only one inductor as it is in screenshot. I know it would be easier just to put...
  4. S

    Purpose of the Capacitor in this filter

    Hi, I do understand that the C5, L3, C6 form a pi filter. But what is the purpose of the other capacitors i.e C8 and C7? What purpose do they serve?
  5. Younes Thabet

    what is the filter used in DC-DC flyback converter input ?

    Hello, I was looking into using something similar to what is used in this reference design by TI. But I didn't understand the input side of this circuit, especially the purpose of the input series resistors and capacitors C1, C2, and C3. Can someone please explain the input side of this...
  6. Stas06

    Effect of 10x Capacitor on Amplifier circuit

    Hi all, I bought capacitors of 22kµ instead of 2.2kµ. I was wondering whetther this circuit could still work with the 22kµ and what the effect is on the circuit. I'm not a electrical engineer so my knowledge is rather limited in this field. My best guess would be that these are used for the...
  7. fujigoata

    LM386 Input filter trouble

    Hello. I am new to electronics and I am trying to complete an LM386 audio amplifier that includes a bandpass filter between 5 and 33 Hz. I know some of the frequencies are outside the frequency range humans can hear. I am testing using a function generator on NI Multisim to get around this. My...
  8. selva97

    Ferrite bead vs Bypass Capacitor

    Why we are using ferrite bead and bypass capacitor, if both are for removing noise? Can you explain why we are using both in the circuit and difference between using them, and where we need to use and how to calculate it?
  9. K

    filtering / shielding for RF power supply from usb-pd

    Hi all, you’re probably going to say this is a dumb idea, but please instead consider it a challenge... I’m trying to build a 12V power supply to use with RF projects. The catch is that I want to try to make it run off of usb-pd, from a usb-pd decoy board. I’m trying to get as clean of a power...
  10. Z

    Finding correct value of components to get the centre frequency of a band reject filter at 30kHz

    Hello! I have to design a band reject filter using two capacitors, two resistors and a load resistor of 1kOhm. I already figured out the appropriate circuit and had derive the transfer function of the filter. I had chose the values for the capacitors, C = 0.01uF and the value of load...
  11. D

    Non-Inverting Amplifier (AC Coupled) : How to solve this circuit with lower and high frequency?

    I need to design this circuit with a gain of 26 for signals where the frequency varies from 800Hz to 8kHz and I also need to find out the current on the RL load. (VA = 100mV) Will C1 behave like an open circuit in ac analysis? I am getting to lower the frequency (800Hz) but I am not able to...
  12. xenon_eleven

    Active Butterworth Bandpass Filter unexpected peak

    I am currently trying to design a bandpass filter in a simulator for a university assignment to the following criteria: Frequencies below 1KHz and above 250KHz should be attenuated. Note that you will need to calculate the cut off frequencies given the pass band (1KHz to 250KHz) should not be...
  13. A

    Three-phase EMI filter. LTspice

    Hello. Could you help me understand how to create a three-phase EMI filter? For example, I chose a full-bridge inverter with parameters P = 100kW, f_switch = 100 kHz. The noise measurement is performed using the LISN. The results of the simulation (calculation time 0-50ms) In this graph...
  14. T

    Could not understand why noise cancellation must be at (fs-fc) for -60dB

    I have the overview of signal with cut-off frequency fc that I want to sample using an ADC with sampling frequency of fs, I have seen that some of my colleagues wanted to dumb any noise at -60dB at frequency fs-fc as you see it in the picture. for my understanding of nyquist theorem, I need to...
  15. C

    Using audio LC filter circuits instead of RC.

    I'm designing a small mixer and stopped at the equalizer section when I recalled the number of small inductors (axial and SMD) in my parts kit. If you search 'filter circuits' or similar you'll ALWAYS get the standard RC topologies, and I'm thinking more of IC feedback types than the usual...
  16. P

    Finding the Size of Inductor and Capacitor

    Hi, i have calculated the L and C value for filter circuit for Three phase inverter, now i would like to know the size and weight of the filter circuit for the L and C value i have calculated. Can anyone help me on how to do this ? Thank you. Raj
  17. S

    8th order sallen-key butterworth lowpass filter

    Hi guys, I'm running into some problems designing a 10MHz 8th order sallen-key butterworth lowpass filter. My requirements are: cornerfrequency f_c = 10 MHz max passband gain of 0.5dB filterorder of 8 available components: resistors, capacitors, op-amps What I have tried so far: I found...
  18. Nurahmed Omar

    Frequency Response of LC Filter has a Peak with an Impedance Load

    Hi, I am designing an LC filter with a cut-off frequency of 20 kHz for the Class-D amplifier. The filter schematic is shown in Fig.1 top right. I understand how to choose the LC values for the critically damped case for the pure resistive load as shown in Fig. 2. The problem is I want to drive...