Lecture 1 - Op-amps

Monday, 17 June 2019

12:04 AM

Amplification Conversion Waveform Generation Multiplication Comparison Filtering Uses Overview of an Op-amp 200px-Op-amp_symbol.svg.png Image result for op amp symbol ﷐𝑉﷮+﷯ - non-inverting input ﷐𝑉﷮−﷯ - inverting input ﷐𝑉﷮𝑆+﷯ and ﷐𝑉﷮𝑆−﷯ are the power supplies for the op-amp, as it is an active device ﷐𝑉﷮𝑜﷯ - gain multiplied by the difference of ﷐𝑉﷮+﷯ and ﷐𝑉﷮−﷯ ﷐𝑉﷮𝑜﷯=﷐𝐴﷮𝑉﷯﷐﷐𝑉﷮+﷯−﷐𝑉﷮−﷯﷯ ﷐𝐴﷮𝑉﷯ - gain factor An op-amp has 2 input terminals, 1 output terminals, and 2 power terminals 𝑛 op-amps would have 𝑛(2 input + 1 output) + 2 =3𝑛+2 terminals Open-loop voltage gain Equivalent circuit OpAmp-Equivalent-Circuit.jpg Image result for op amp equivalent circuit Ideal Characteristics ﷐𝑍﷮𝑖𝑛﷯ is very large ﷐𝑍﷮𝑜𝑢𝑡﷯ is very small Common Mode Rejection Ratio (CMRR)
Common Mode Rejection Ratio (CMRR) 𝑟𝑎𝑡𝑖𝑜=﷐﷐𝐴﷮𝑑﷯﷮﷐𝐴﷮𝑐﷯﷯ ﷐𝐴﷮𝑑﷯ - differential gain ﷐𝐴﷮𝑐﷯ - common voltage Better op-amps have a higher CMRR An op-amp should draw little to no current The realistic drawn current is the input bias Input Bias Current Virtual ground: ﷐𝑉﷮−﷯=﷐𝑉﷮+﷯ No current enters the input terminals Golden Rules for Analysing an Op-amp Op-amp Types Inverting Amplifier Inverting-Amplifier-using-Opamp-Circuit-Diagram.jpg Image result for inverting input op amp ﷐𝑉﷮+﷯=0=﷐𝑉﷮−﷯ (Voltage is zero as ﷐𝑉﷮+﷯ is grounded) ∑𝐼=0 ﷐𝑖﷮1﷯+﷐𝑖﷮2﷯−﷐𝑖﷮−﷯=0 As ﷐𝑖﷮−﷯=0 ﷐𝑖﷮1﷯+﷐𝑖﷮2﷯=0 ﷐﷐𝑣﷮𝑖𝑛﷯−﷐𝑣﷮−﷯﷮𝑅1﷯+﷐﷐𝑣﷮𝑜𝑢𝑡﷯−﷐𝑣﷮−﷯﷮𝑅𝑓﷯=0 ﷐﷐𝑣﷮𝑜𝑢𝑡﷯﷮﷐𝑣﷮𝑖𝑛﷯﷯=−﷐𝑅𝑓﷮𝑅1﷯ Untitled picture.jpg Machine generated alternative text: Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings Ink Drawings
Untitled picture.jpg Machine generated alternative text: KVL @ A: −﷐𝑉﷮𝑜𝑢𝑡﷯+﷐𝑅﷮𝑜﷯𝐼−﷐𝐴﷮𝑣﷯﷐𝑉﷮𝑖﷮′﷯=0 KVL @ B: −﷐𝑅𝑖﷮﷐𝑅﷮𝑖﷯+𝑅1﷯﷐𝑉﷮𝑖﷯+(﷐𝑅﷮𝑖﷯|﷐𝑅1+𝑅𝑓+﷐𝑅﷮𝑜﷯﷯𝐼−﷐𝐴﷮𝑉﷯﷐𝑉﷮𝑖﷯=0 Loop BLUE: −﷐﷐𝑅﷮1﷯﷮﷐𝑅﷮𝑖﷯+𝑅1﷯+(﷐𝑅﷮𝑖﷯|﷐𝑅1﷯𝐼+﷐𝑉﷮𝑖﷯=0 /// Untitled picture.jpg Machine generated alternative text: Okay we good Untitled picture.jpg / 1 い ⅵ り ら ら ・ こ 一 こ ウ 1 ~ ニ / し は 阯 て - 、 ラ し 1 = / 1 当 ・ い h 。 レ = ・ 1 〆 - に い 靖
Untitled picture.jpg / 1 い ⅵ り ら ら ・ こ 一 こ ウ 1 ~ ニ / し は 阯 て - 、 ラ し 1 = / 1 当 ・ い h 。 レ = ・ 1 〆 - に い 靖 ///

 

Created with Microsoft OneNote 2016.