1 / 15

Anglicky v odborných předmětech "Support of teaching technical subjects in English “

Anglicky v odborných předmětech "Support of teaching technical subjects in English “. Tutorial : Mechanic – electrician Topic : Electronics II. class RC Filters : RC High Pass Filter Prepared by: Ing. Jaroslav Bernkopf.

dean-chavez
Télécharger la présentation

Anglicky v odborných předmětech "Support of teaching technical subjects in English “

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Anglicky v odborných předmětech"Support ofteachingtechnicalsubjects in English“ Tutorial: Mechanic– electrician Topic: Electronics II. class RC Filters: RC HighPassFilter Prepared by: Ing. Jaroslav Bernkopf Projekt Anglicky v odborných předmětech, CZ.1.07/1.3.09/04.0002 je spolufinancován Evropským sociálním fondem a státním rozpočtem České republiky.

  2. Definition A high-pass filter is a circuit that passes high-frequency signals but attenuates signals with frequencies lowerthan the cutoff frequency. -3 dB Slope: 20 dB/decade (6 dB/octave) Cutofffrequency Stopband Passband f RC Filters

  3. Description The simplest high-pass filter consists of one resistor and one capacitor. We call it the RC high-pass filter. -3 dB Slope: 20 dB/decade (6 dB/octave) A Cutofffrequency Stopband Passband f RC Filters

  4. Description Let‘sconstructthegain-frequencycharacteristicofthe RC high-pass filter. Let‘s apply a voltage Vinof a very lowfrequency to the input of the circuit. If the frequency becomeslower and lower, the input voltagewillbecome a DC voltage. No DC currentcanpassthroughthecapacitorbecausethereisaninsulatorbetweenitselectrodes. No DC signalcanpassfromthe input ofthiscircuit to its output. 1 Av 0 f RC Filters

  5. Description At zerofrequencytheoutput voltageVoutwillbezero: = The voltage gain Av is 1 Av 0 f = 0 f Av = 0 RC Filters

  6. Description We have the firstpoint of the gain-frequency characteristic: At zerofrequency the voltage gain Av is equal to zero. 1 Av 0 f = 0 f Av = 0 RC Filters

  7. Description Let‘s apply a voltage Vin of a very high frequency and ofanamplitudeof 10V to the input of the circuit. At a very high frequency the capacitor represents a short circuit – similar to a wire link. If the output pin is shorted with the input pin, there mustbe thesamesignal on it. 1 Av 0 f RC Filters

  8. Description The output voltage Vout is the same as the input voltage Vin = 10 V. Therefore = The voltage gain Av is We have the second point of the gain-frequency characteristic: At infinitefrequency the voltage gain Av is equal to unity. 1 Av Av = 1 0 f f = ∞ RC Filters

  9. Description Between these two points there is a point where the gain stopsrisingand starts to be unity. We call this point the cutoff frequency. 1 Gainis unity Av = 0,707 Av Gainis rising 0 f fc RC Filters

  10. Description In thepassbandallsignalpassesfromthe input to the output. ThevoltagegainAvisequal to unity. -3 dB Slope: 20 dB/decade (6 dB/octave) A Cutofffrequency Stopband Passband f RC Filters

  11. Description In thestopbandthelowerthefrequency, thelowerthevoltagegainAv. ThegainAvfalls off at 20dB per decade (or 6dB per octave, whichtellsthesame). When the frequency decreases by a factor of 10, the gain decreasesby a factor of 10 (i.e. 20 dB). When the frequency decreases by a factor of 2, the gain decreases by a factor of 2 (i.e. 6 dB). -3 dB Slope: 20 dB/decade (6 dB/octave) A Cutofffrequency Stopband Passband f RC Filters

  12. Description At thecutofffrequencyfcthevoltagegainAvfalls to . In otherwordsthegainisreduced by 3 dB. Hereis the formula for the cut-off frequency: -3 dB Slope: 20 dB/decade (6 dB/octave) A Cutofffrequency Stopband Passband f RC Filters

  13. Task Calculate the cut-off frequency for the circuit below and state if it is a high pass or low passfilter. 10k 10n RC Filters

  14. Solution Thecut-offfrequencyofthecircuitis 1 592 Hz. A signalofthelowestfrequency – a DC signal – can‘tpassthroughthecapacitorbecausethereisaninsulatorbetweenitselectrodes. A signalof a highfrequencypasseswithoutattenuationbecausethecapacitorrepresents a shortcircuit. Thecircuitis a high-passfilter. 10k 10n RC Filters

  15. References • http://www.wikipedia.com • http://www.thefreedictionary.com • http://www.animations.physics.unsw.edu.au/jw/calculus.htm • http://openlearn.open.ac.uk/ RC Filters

More Related