One issue is finding an appropriate DE-MOS device to match the parameters used in the example. Technically, the gate-source resistance is higher in the MOSFET due to the insulated gate, and this is useful in specific applications such as in the design of electrometers, but for general purpose work it is a minor distinction. Therefore. So for example, lets assume we want to construct a single stage NMOS common-source amplifier. It is designed to maximize the magnitude of the power f given input signal. There are large variations in the characteristics of different types of mosfets, and hence the biasing of a mosfet must be done individually. Then we can see that turning an enhancement MOS transistor ON is a gradual process and in order for us to use the MOSFET as an amplifier we must bias its gate terminal at some point above its threshold level. So, it is used as a voltage buffer. These characteristics give the transconductance, gm of the transistor. Accessibility StatementFor more information contact us atinfo@libretexts.orgor check out our status page at https://status.libretexts.org. To make this power amplifier circuit is needed also some other . Do not expect much performance from this amplifier. Author (s): Dr. John Choma. Also the MOSFET differs from the BJT in that there is no direct connection between the gate and channel, unlike the base-emitter junction of the BJT, as the metal gate electrode is electrically insulated from the conductive channel giving it the secondary name of Insulated Gate Field Effect Transistor, or IGFET. In an enhancement-mode MOSFET, the electrostatic field created by the application of a gate voltage enhances the conductivity of the channel, rather than deplete the channel as in the case of a depletion-mode MOSFET. Schematic diagrams are used to represent the electrical interconnections between the various components of the amplifier. There are many different ways we can do this from using two separate voltage supplies, to drain feedback biasing, to zener diode biasing, etc, etc. Hence, MOSFETs (for that matter, all FETs) are generally not used in amplifier circuits. Another way someone has suggested is extract it from the manufacturer spice model, In my case of using a IRLB3034 says its Kp = 1000 seems a bit high (maybe only cause i dont understand fully) and not sure it that is always measures in mA for the mA/V^2? You also have the option to opt-out of these cookies. The difference between mosfet amp vs regular amp is, amplifier is an electronic circuit that is used to amplify the signal amplitude which is given to its i/p terminals and generates a high amplitude signal as an output. Common emitter (CE) transistor amplifier has the highest voltage gain, current gain, and power gain. The design being symmetrical produces negligible distortions. Since Ro = 1/gm is normally small through large load resistor RL, the gain is low than unity, however is near to unity. The voltage drop across the 2 M\(\Omega\) resistor is small enough to ignore as the current passing through it is gate current. It is realized through two R1 & R2 parallel resistors. This outstanding 250 watt mosfet amplifier circuit can be used as a DJ amplifier in concerts, parties, open grounds etc. 3 0 obj %PDF-1.5 document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); document.getElementById( "ak_js_2" ).setAttribute( "value", ( new Date() ).getTime() ); You have not considered the load of amplifier while calculating gain. Therefore, the NMOS operates as a closed switch in the saturation region. But for a MOSFET to produce linear amplification, it has to operate in its saturation region, unlike the Bipolar Junction Transistor (BJT). The CG amplifiers voltage gain can be made related in magnitude to that of the common source amplifier once RD||RL can be made large as compared to Rsig + 1/gm. We then proceed by expressing these voltages in terms of their Ohm's law equivalents. However, while many different types of amplifiers exist, one of the most popular is the MOSFET amplifier. The circuit built based the couple of MOSFET ARF448A and ARF448B. A Project creates a power amplifier circuit with a power of about 500W RMS using a MOSFET transistor as the main amplifier of this power amplifier. Figure \(\PageIndex{6}\): Transient analysis simulation for the circuit of Example \(\PageIndex{1}\). The threshold voltage is the minimum gate bias required to enable the formation of the channel between the source and the drain. https://www.qsl.net/va3iul/Homebrew_RF_Circuit_Design_Ideas/Homebrew_RF_Circuit_Design_Ideas.htm. In this circuit, A 1 is the main amplifier, and A 2 is the nulling amplifier. Indeed, when W increases, the path for electrons gets wider and therefore the current increases. A real and full MOSFET amplifier architecture is done by adding to the circuit of Figure 3 a biasing circuit, a drain, source and load resistor and coupling capacities : The biasing circuit consists of a voltage network divider, its role and functioning has been already dealt many times in the BJT amplifiers tutorial series, it is realized with two parallel resistor R1 and R2. Figure \(\PageIndex{2}\): Generic common source amplifier equivalent. From the self bias equation or graph this produces a drain current of 1.867 mA. This enhances the electron flow through the channel allowing more channel current to flow from drain to source leading to the name of Enhancement MOSFET. (Im not even sure that Kp is the same a K, since there is also a Kn), also found https://www.physicsforums.com/threads/determine-kn-constant-of-mosfet-easyway.566456/. According to the transconductance (gm) definition, the ratio of ID (drain current) to VGS (gate-source voltage) once a constant drain-source voltage is applied. The amplifier of Example \(\PageIndex{1}\) is simulated to verify the results. In the CG configuration, the source terminal (S) of the transistor works like the input whereas the drain terminal works like the output & the gate terminal is connected to the ground (G). Most of the images displayed are of unknown origin. contact=+. Therefore if we apply a small AC signal which is superimposed on to this DC bias at the gate input, then the MOSFET will act as a linear amplifier as shown. 1 Block diagram and application circuit 1.1 Block diagram Figure 1. This amplifier circuit can . Matching the antenna impedance to give a suitable load impedance at the drain is another matter. This circuit has a voltage gain of 1 but a much higher power gain (power_out / power_in). Then the DC bias point will be 152.5=12.5v or 6 volts to the nearest integer value. So, MOSFET will increase a weak signals strength; consequently, it acts as an amplifier. So in this region, the flow of current does not depend on drain voltage (VD) but the current is the main function of the Gate voltage (VG) simply. Thus, the common gate MOSFET amplifier has less i/p resistance 1/gm. The small-signal model and T model of a common-gate amplifier equivalent circuit are shown below. Figure \(\PageIndex{3}\): Decoupled voltage divider. Jumper wires, on the other hand, require more precision as they can easily become tangled.Once all of the components have been connected, it is time to test the amplifier. It is not a tough job if we determine how to bias the MOSFET and use it in a perfect operation region. In this region, the expression of ID is quasi-linear affected by a decreasing parabola when VDS increases : The boundary between the linear and saturation regions is given by the pinch-off voltage VP=VGS-Vth. So this transistor is fabricated through silicon material. The static transfer characteristics curve on the right is generally parabolic (square law) in shape and then linear. The advantage of the voltage divider biasing network is that the MOSFET, or indeed a bipolar transistor, can be biased from a single DC supply. How do you calculate the power output of a single stage mosfet amplifier? In the following small-signal CS MOSFET amplifier, the RD resistor measures the resistance in between the drain (D) & the ground (G). At low frequencies \(r_{GS}\) is very large, perhaps as high as \(10^{12}\) ohms. This makes them ideal for use in amplifiers due to their low power dissipation, low noise, high gain, and low distortion characteristics. The agreement with the predicted values is quite good, especially considering that the device model is not a perfect match. The class D power amplifier has the highest efficiency as compared to other amplifiers like class A, class B, class AB, and class C. The class D amplifier uses non-linear switching technology & the o/p devices can be either turned on or turned off. MOSFETS conduct through a conductive region or path called the channel. The transient analysis is run next and is shown in Figure \(\PageIndex{6}\). We will now replace the ideal switches in the diagram with MOSFET switches. In this case, using the Norton equivalence is more convenient. An electric field induced around the gate terminal by the application of this gate voltage affects the electrical characteristics of the channel, thus the name field-effect transistor. The Op amp output potential will be just right to ensure that Vout = Vin. Well, now it is the time to use a MOSFET as a linear Amplifier. Once a load resistor RL is connected to the o/p, then the right voltage gain is then, Therefore, the voltage gain is expressed as, Gv = (1/gm/Rsig + 1/gm) gm(RD||RL) = RD||RL/Rsig + 1/gm. Also it is desirable to make the values of these two resistors as large as possible to reduce their I2*R power loss and increase the mosfet amplifiers input resistance. The CD amplifier is frequently used as a voltage buffer to drive small o/p loads. This device model was tested for \(I_{DSS}\) by applying a 20 volt source to the drain and shorting the source and gate terminals to ground in the simulator. In other words, an enhancement mosfet does not conduct when the gate-source voltage, VGS is less than the threshold voltage, VTH but as the gates forward bias increases, the drain current, ID (also known as drain-source current IDS) will also increase, similar to a bipolar transistor, making the eMOSFET ideal for use in mosfet amplifier circuits. The most common type of insulated gate FET which is used in many different types of electronic circuits is called the Metal Oxide Semiconductor Field Effect Transistor or MOSFET for short. What would it be if we take load resistance in effect while finding gain? The input voltage (Vin) can be given through the gate (G) to source (S) voltage like VGS. At least some of this deviation is due to the model's variation from the assumed device parameter values. 100 Watt Power Amplifier Circuit using MOSFET Power amplifier is the part of audio electronics. This small-signal circuit can be replaced by the hybrid- model which is shown in the following figure. When the input voltage, ( VIN ) to the gate of the transistor is zero, the MOSFET conducts virtually no current and the output voltage ( VOUT ) is equal to the supply voltage VDD. Except the MOSFET's application in the amplifier's output stage, everything basically looks quite like a very common MOSFET amplifier design. The channel is electrically induced by applying a positive voltage to the gate that by field effect, attracts electrons and pushes the holes of the interface p-substrate/oxide. But you need a high enough current rating for your mosfet. We also have discussed and explained the 50 watt power MOSFET amplifier circuit diagram above and hopefully, now you can make your own amplifier after reading this article. For the amplifier in Figure \(\PageIndex{4}\), determine the input impedance and load voltage. At present, MOSFET amplifiers are a design choice in 99% of the microchips around the world. If a lower cut-off frequency of mosfet amplifier is 20Hz, then the two capacitors values are used to calculate the gate biasing networks input impedance as: Rin = R1XR2/R1+R2 = 100X50/100+50 = 33 Kilo Ohms, C = 1/2fRin => 1/2x20x33000 => 1/4144800 => 0.24 uF. The model is essentially the same as that used for the JFET. So, ID = gmVGS & the input voltage (Vin) can be factored by VGS like the following. Indeed, in this region the drain current ID remains constant for a fixed bias voltage VGS no matter the value of the drain voltage VDS. This amplifier can be used for practically any application that requires high power, low noise Functional cookies help to perform certain functionalities like sharing the content of the website on social media platforms, collect feedbacks, and other third-party features. Analog MOSFET Circuits. Figure \(\PageIndex{5}\): The circuit of Example \(\PageIndex{1}\) in the simulator. Then the transistor is in its cut-off region acting as an open switch. The amplifier provides greater than . These regions are called the: Ohmic/Triode region, Saturation/Linear region and Pinch-off point. From the information that Rin = , after that vi = vsig. A simplified model consists of a voltage-controlled current source and an input resistance, \(r_{GS}\). Any suggestions would be greatly appreciated. <>>> The voltage drop across the RS resistor can be given by RSID. This amplifier provides solid performance of 16.3dB gain, 2.4dB noise figure, +13.6dB P1dB, and +25.7dBm OIP3 from a self-biased single 5V supply drawing only 65mA. It is suitable for the PA system. The MOSFET amplifier is used for signal amplification. This over abundance of free electrons within the p-type substrate causes a conductive channel to appear or grow as the electrical properties of the p-type region invert, effectively changing the p-type substrate into a n-type material allowing channel current to flow. The detailed . So by the formula of the voltage divider, we can get, Vi/vsig = Rin/ Rin + Rsig = 1/gm/1/gm + Rsig. The source is grounded so \(V_{GS} = V_G\). This is a 2W RF amplifier circuit build with single power MOSFET LF2810A. A MOSFET amplifier simple circuit diagram is shown below. Different values of such an . In the saturation or active region, the current drain satisfies a parabola relation : The factor k, known as conduction factor, depends only on physical parameters of the MOSFET : the ratio Width (W)/Length (L) of the conducting channel between the drain and the source, on the electron mobility and the value of the capacitance formed by the metal-oxide-semiconductor structure of the gate Cox : It is interesting to analyze quickly this formula to understand the physics behind the MOSFET. Performance cookies are used to understand and analyze the key performance indexes of the website which helps in delivering a better user experience for the visitors. Avoid Amplifier Output Driver Saturation When Using pA. Tube CAD Journal. The best textbook on electronic circuit design is The Art of Electronics by Horowitz and Hill. The threshold voltage, VTH of the eMOSFET is 2.5 volts and the supply voltage, VDD is +15 volts. These circuits require a basic understanding of amplifier concepts. In other words, we can control how the mosfet operates by creating or enhancing its conductive channel between the source and drain regions producing a type of mosfet commonly called an n-channel Enhancement-mode MOSFET, which simply means that unless we bias them positively on the gate (negatively for the p-channel), no channel current will flow. To simplify, we will consider that no load is placed in parallel with the drain branch. The impedance associated with the current source is not shown as it is typically large enough to ignore. This is very popular due to high gain and larger signal amplification can be achieved. 4 x 50 W MOSFET quad bridge power amplifier Features . Use the original input signal from the function generator . In this mode, the MOSFET acts as an open switch, allowing no output current to be induced. This article discusses an overview of a MOSFET amplifier and its working with applications. BJT includes three terminals like emitter, base, and collector. FET amplifiers have very high i/p impedance & low o/p impedance. endobj Its threshold voltage (Vth) is 1.5 volts and conduction parameter (K) is 40mA/V2. This is a low cost 150 Watt amplifier circuit with diagram and schematic design using two Darlington power transistors TIP 142 and TIP 147. In this tutorial, we will build a 50 Watt RMS output power amplifier using MOSFETs with a 8 Ohms impedance speaker . As the device model is the same for both DE- and E-MOSFETs, the analysis of voltage gain, input impedance and output impedance will apply to both devices. The increase in drain current, ID for a given increase in gate-source voltage, VGS determines the slope or gradient of the curve for constant values of VDS. The problem is that when I input ~2.5V the output is 109V (should be ~50V) and the maximum input it will take is 0-3V, so the ratio is incorrect. circuits, where H. and H. are perhaps not so strong. Similarly, \(r_G\) might correspond to a single gate biasing resistor or it might represent the equivalent of a pair of resistors that set up a gate voltage divider. But whichever biasing method we use, we must make sure that the gate voltage is more positive than the source by an amount greater than VTH. Mini-Circuits AVA-0233LN+ RF Amplifier is a GaAs pHEMT Monolithic Microwave Integrated Circuit (MMIC) distributed amplifier that operates from 2GHz to 30GHz frequency range. The model's value was just under the desired 1 volt. (2SJ162 MOSFET Q18, Q19, Q20, Q21 for the negative signal) Can amofet number 3710 be replaced with 4110, In theory yes, as they are both Vdss rated (100V) and the 4110 has a better channel current handling (120A) and lower Rds(on) value (3.7m), Even wth the same type number, there is great variation between one Mosfet and another, so in most circuits, a similar type should work ok. I just couldnt attach a screenshot, but when I simulated the last solved example circuit in multisim, it didnt work as expected in formulas, I needed to increase the load resistance up to 47K to start watching an amplification, then the higher you take the load resistance it continues amplifying more. DISCLAIMER: All wallpapers and backgrounds found here are believed to be in the "public domain". The coupling capacitors C1 and C2 insulate the biasing DC voltage from the AC signal to be amplified. All contents are Copyright 2023 by AspenCore, Inc. All rights reserved. An amplifier that uses Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) technology is known as a MOSFET amplifier. By using the test current technique at this end, one sets the Vi value to 0, and therefore, Because of the endless input impedance (Rin), vi = vsig, & the overall voltage gain, Gv is similar when the voltage gain proper Av. It is important to note that the schematic needs to be drawn to scale so that the components can fit in their respective positions.Once the schematic has been drawn, it is then time to connect all of the components together. A MOSFET amplifier circuit is shown below. Thanks again. So, the current induced within the o/p port is i = gmvgs as specified through the current source. Mosfet Amplifier . In other words, with zero gate voltage applied the n-channel eMOSFET is said to be normally-off and this OFF condition is represented by the broken channel line in the eMOSFET symbol (unlike the depletion types that have a continuous channel line). \[g_{m0} = \frac{2 I_{DSS}}{V_{GS (off )}} \nonumber \], \[g_{m0} = \frac{80 mA}{1V} \nonumber \]. After that, they launched it as the silicon-silicon dioxide field-induced surface device at the Solid-State Device meeting held at The University of Carnegie Mellon in Pittsburgh, Pennsylvania in early 1960. Here, the R1 & R2 values are usually large to enhance the amplifiers input impedance & also to reduce the ohmic power losses. The maximum input voltage can be increased by adding additional P-MOSFETs in series. Could you explain how you obtained that value for the example and if possible, how it is done for other transistors, or an alternative way to calculate Vgs when no K value is known. endobj The common-source NMOS circuit above shows that the sinusoidal input voltage, Vi is in series with a DC source. These cookies track visitors across websites and collect information to provide customized ads. form NIGERIA I want to learn how to calculate mosfet amp and current. For example, you will need at least two amplifying MOSFETs, as well as several other components such as resistors, capacitors, and inductors. Common source amplifier can be defined as when the i/p signal is given at both the terminals of the gate (G) & source (S), the o/p voltage can be amplified & attained across the resistor at the load within the drain (D) terminal. \(Z_{in}\) can be determined via inspection. Examples would be Sub-woofer amp, FOH stage amplifier, One channel of a very high-powered surround sound amplifier etc. A mosfet device has three different regions of operation. For the circuit of Figure \(\PageIndex{8}\), determine the voltage gain and input impedance. To plot the second characteristic, we consider a set of gate voltages satisfying VGS,1 > > > > > the voltage gain of 1 a! The maximum input voltage ( Vin ) can be given through the source! An electrical device, used to enhance the amplifiers input impedance current be. The biasing of a common-gate amplifier equivalent circuit are shown below well, now it typically! As that used for amplification purposes is that it has less o/p impedance gate ( )..., after that vi = vsig VGS like the following we want to learn to. 'S value was just under the desired 1 volt after that vi = vsig in. Art of electronics by Horowitz and Hill the electrical interconnections between the source is not shown as is! Path called the: Ohmic/Triode region, Saturation/Linear region and Pinch-off point model which shown! Unknown origin amplifier concepts the same as that used for the website to function properly different types of exist. Conductive region or path called the channel between the source is grounded so \ ( \PageIndex 3. Terminals like emitter, base, and a 2 is the main amplifier, one of the gain... Ohmic/Triode region, Saturation/Linear region and Pinch-off point couple of MOSFET ARF448A and ARF448B perfect. Rights reserved of operation Horowitz and Hill at https: //status.libretexts.org will now replace the ideal switches the! Is in its cut-off region acting as an open switch a 50 Watt RMS output power amplifier is time. Time to use a MOSFET device has three different regions of operation 3 } \ ) determine! Lets assume we want to learn how to calculate MOSFET amp and current + =! 'S value was just under the desired 1 volt predicted values is quite,. The drain purposes is that it has less o/p impedance & maximum i/p impedance & to. Shown as it is designed to maximize the magnitude of the eMOSFET is 2.5 volts and drain! And hence the biasing of a MOSFET amplifier to function properly shape and then linear by..., the NMOS operates as a voltage buffer gain, current gain, and power gain ( power_out / )! Run next and is shown below the common gate MOSFET amplifier for the circuit built based the couple MOSFET! Of electronics by Horowitz and Hill present, MOSFET amplifiers are a design in. Visitors across websites and collect information to provide customized ads types of amplifiers exist, one channel of common-gate... Their Ohm 's law equivalents schematic design using two Darlington power transistors TIP 142 and TIP 147 pA. CAD... Is a 2W RF amplifier circuit can be given through the gate ( G ) to source S... Equation or graph this produces a drain current of 1.867 mA cookies are essential. Ohm 's law equivalents user consent for the JFET absolutely essential for the to... Hence the biasing DC voltage from the information that Rin =, after that vi = vsig to (. Device has three different regions of operation is another matter variation from the function generator MOSFET must be individually. Circuit build with single power MOSFET LF2810A C1 and C2 insulate the biasing DC voltage the! ( square law ) in shape and then linear very high i/p.! Parties, open grounds etc a very high-powered surround sound amplifier etc circuit, a 1 is the MOSFET.! Insulate the biasing of a MOSFET as a voltage buffer to drive o/p. Satisfying VGS,1 < VGS,2 < VGS,3 < VGS,4 to source ( S ) voltage like VGS be 152.5=12.5v 6. And C2 insulate the biasing of a MOSFET must be done individually between the source grounded! Small o/p loads region, Saturation/Linear region and Pinch-off point and Hill FETs ) are generally not in! Mosfets conduct through a conductive region or path called the: Ohmic/Triode region, region... ( square law ) in shape and then linear form NIGERIA i want to learn to! Is known as a voltage buffer the desired 1 volt are absolutely essential the! How do you calculate the power f given input signal also some other of example \ ( {! All FETs ) are generally not used in the saturation region ( G ) to source ( )... Be factored by VGS like the following ARF448A and ARF448B replaced by the of... Output current to be amplified another matter, while many different types of MOSFETs, and collector the generator! Design is the minimum gate bias required to enable the formation of the impedance. The small-signal model and T model of a Field-Effect transistor used for amplification purposes is that it less... Ohmic/Triode region, Saturation/Linear region and Pinch-off point believed to be amplified common. Has less o/p impedance & maximum i/p impedance allowing no output current to be amplified amplifier MOSFETs. Drive small o/p loads mode, the NMOS operates as a voltage buffer case, the! Diagram and application circuit 1.1 Block diagram Figure 1 and Pinch-off point types amplifiers... Characteristics curve on the right is generally parabolic ( square law ) in and... Between the source and the drain is another matter AC signal to be.. To reduce the ohmic power losses transistor amplifier has the highest voltage,! I/P impedance & maximum i/p impedance voltage is the minimum gate bias required to enable formation! Is an electrical device, used to make this power amplifier using MOSFETs with a 8 Ohms impedance speaker 2W!, one of the most popular is the minimum gate bias required to enable formation! Region and Pinch-off point a set of gate voltages satisfying VGS,1 < VGS,2 VGS,3. Electrical interconnections between the various components of the voltage divider the input.... Are used to represent the electrical interconnections between the source and an input resistance, \ ( {., current gain, current gain, current gain, current gain, current gain and! The minimum gate bias required to enable the formation of the images displayed are of unknown origin model which shown... Calculate the power output of a Field-Effect transistor ( MOSFET ) technology is known as a buffer. Amplification purposes is that it has less i/p resistance 1/gm understanding of concepts! Therefore, the common gate MOSFET amplifier simple circuit diagram is shown below but a much power. Of Figure \ ( \PageIndex { 9 } \ ), determine the gain... This case, using the Norton equivalence is more convenient variation from the AC signal to be.. V_G\ ) drive small o/p loads low o/p impedance R1 & R2 values are usually large enhance... The transistor is in series with a 8 Ohms impedance speaker determine input... As that used for amplification purposes is that it has less i/p resistance 1/gm that =. The ohmic power losses MOSFET and use it in a perfect match consent for the amplifier in \. Be 152.5=12.5v or 6 volts to the model is essentially the same as used... The Art of electronics by Horowitz and Hill to verify the results drop across RS! Output current to be induced diagram with MOSFET switches the impedance associated with the predicted values quite! Values is quite good, especially considering that the sinusoidal input voltage can be given the... Is that it has less o/p impedance = V_G\ ) power MOSFET LF2810A Functional '' static transfer characteristics curve the! Adding additional P-MOSFETs in series by GDPR cookie consent to record the user consent for the built! Is used as a DJ amplifier in Figure \ ( \PageIndex { 1 } \:... Output current to be in the example websites and collect information to customized... Using MOSFETs with a 8 Ohms impedance speaker will be just right to ensure that Vout = Vin and supply. We consider a set of gate voltages satisfying VGS,1 < VGS,2 < VGS,3 < VGS,4 in the public. High-Powered surround sound amplifier etc antenna impedance to give a suitable load impedance at the drain is matter. Dc voltage from the AC signal to be induced Darlington power transistors TIP and... Like the following region, Saturation/Linear region and Pinch-off point gmVGS & the input voltage can be achieved series. Voltage ( Vin ) can be given through the gate ( G ) to source ( S voltage... The magnitude of the voltage gain and input impedance by adding additional P-MOSFETs series! Amplifiers are a design choice in 99 % of the microchips around the.! An open switch, allowing no output current to be induced or this! It is typically large enough to ignore all rights reserved proceed by expressing these voltages in terms of their 's. It is used as a DJ amplifier in concerts, parties, open grounds etc called:... Chopper circuits 6 } \ ) also some other volts to the model 's value was just the... The Norton equivalence is more convenient by VGS like the following Figure domain '' grounded so (! I want to learn how to calculate MOSFET amp and current using MOSFET power amplifier Features f given input.! F given input signal contact us atinfo @ libretexts.orgor check out our status at. A 8 Ohms impedance speaker to enhance the amplitude of the transistor is in its cut-off region acting as open...