Change to Ukrainian interface versionChange to English interface versionChange to Russian interface versionHome pageClear last query resultsHelp page
Search for specific termsBrowse by subject categoryBrowse alphabetical list of titlesBrowse by organizationBrowse special topic issues

close this bookAmplifier Teaching Aid (GTZ, DED; 86 pages)
View the documentPreface
View the documentIntroduction
Open this folder and view contentsLesson 1 - Semiconductor Review
Open this folder and view contentsLesson 2 - Bipolar Transistor
Open this folder and view contentsBipolar Transistor II
View the documentFirst Evaluation
Open this folder and view contentsLesson 4 - Transistor Fundamentals
Open this folder and view contentsLesson 5 - Transistor Biasing
Open this folder and view contentsLesson 6 - Transistor Biasing II
View the documentSecond Evaluation
close this folderLesson 7 - Small Signal Amplifier
close this folderLesson Plan
View the documentSmall signal amplifier
View the documentCoupling capacitor
View the documentBypass capacitor
View the documentAmplifier analyzing method
View the documentWorksheet No. 7
View the documentExperiment No. 4
Open this folder and view contentsLesson 8 - Small Signal Amplifier II
Open this folder and view contentsLesson 9 - Small Signal Amplifier III
Open this folder and view contentsLesson 10 - Large Signal Amplifier
View the documentThird Evaluation
 

Coupling capacitor

A capacitor is open at low frequencies and shorted at high frequencies.

Capacitive reactance (XC) is inversely proportional to frequency (f) and to capacitance (C). For a coupling capacitor to work properly, it has to act like an ac short at the lowest frequency that the ac source can have. To realize that we can use the following rule:

XC < 10 R
Make the reactance at least 10 times smaller than the total resistance in series with the capacitor.

Ex: Calculate the capacitance of C1 for a proper ac transmittance. Frequency range: 20-20000 Hz


Fig. 7-1: Use of coupling capacitor

Total resistance: 1KΩ + 500Ω = 1.5KΩ

XC <= 10 * R -- >


-- >

C = 53μF

The capacitor to choose should be bigger than 53μF. The next standard value is:

C = 56μF
to previous section to next section

[Ukrainian]  [English]  [Russian]