The C's impedance is 1/sC or 1/2pifC. when 1/sC=R, a transition point, also called -3dB point in power, since the output is exactly 50% of input voltage. For power, dB=10log(Pout/Pin). For V, I or R, dB=20log(Vout/Vin). So for Vout/Vin, 1/sC=R is -6dB on the vertical scale or 20log(0.5Vin/Vin)=-6dB. Why -20dB, decade in frequency in a factor of 10. If f_pole=1kHz, one decade is 10kHz. Simulate RC circuit in LTSpice with R=10k, C=0.01u, f_pole=1/2piRC=1.591kHz. If you check the dB value at 15.91kHz, you will see the Vout/Vin in dB will be measured at -20dB, hence the output ratio in voltage is falling at a rate of -20dB/dec. At 159.1kHz, the dB value will be at -40dB, because it is 2 decade awa from f_pole. Hope this helps.
amazinge
It helped like anything else, I can't thank you enough with words,, God bless you
thank you Mark Ruffalo for explaining this so well
is there more lectures for LTspice?
Could you please explain me What is S? it is 2 times pi times F?
why are we looking at when the impedances of R and C are the same at 5:22? Why is the result -20db down? Why do we fix the values and call it a pole?
can you please help me so I can understand this video, otherwise its very confusing
The C's impedance is 1/sC or 1/2pifC. when 1/sC=R, a transition point, also called -3dB point in power, since the output is exactly 50% of input voltage. For power, dB=10log(Pout/Pin). For V, I or R, dB=20log(Vout/Vin). So for Vout/Vin, 1/sC=R is -6dB on the vertical scale or 20log(0.5Vin/Vin)=-6dB. Why -20dB, decade in frequency in a factor of 10. If f_pole=1kHz, one decade is 10kHz. Simulate RC circuit in LTSpice with R=10k, C=0.01u, f_pole=1/2piRC=1.591kHz. If you check the dB value at 15.91kHz, you will see the Vout/Vin in dB will be measured at -20dB, hence the output ratio in voltage is falling at a rate of -20dB/dec. At 159.1kHz, the dB value will be at -40dB, because it is 2 decade awa from f_pole. Hope this helps.
@@leiaz6762 I'm so sorry, I thought I responded to this right after, this was very helpful thank you so much for explaining, I really appreciate it