View source for User:John R. Brews/Circuits

==Circuits==
{{Gallery-mixed
|caption=Current sources
|width=200
|lines=5
|Widlar Current Source.PNG|Widlar current source using bipolar transistors
|Widlar small-signal.PNG|Small-signal circuit for finding output resistance of the Widlar source
|Widlar Resistance Plot.PNG|Design trade-off between output resistance and output current in Widlar source
|Simple bipolar mirror.PNG|A current mirror implemented with npn bipolar transistors using a resistor to set the reference current I<sub>REF</sub>; V<sub>CC</sub><nowiki> = </nowiki>supply voltage.
|Simple MOSFET mirror.PNG| An n-channel MOSFET current mirror with a resistor to set the reference current
|Gain-assisted current mirror.PNG| Gain-boosted current mirror with op amp feedback to increase output resistance.
|Wide-swing MOSFET mirror.PNG| MOSFET version of wide-swing current mirror; M<sub>1</sub> and M<sub>2</sub> are in active mode
|Current sink.PNG|Operational-amplifier based current sink. Because the op amp is modeled as a nullor, op amp input variables are zero regardless of the values for its output variables.
|Bipolar inverter.PNG|A digital inverter circuit using a bipolar transistor.
|Transfer characteristic of bipolar inverter.PNG|Transfer characteristic of bipolar inverter showing modes.
|Current in bipolar inverter.PNG|Collector current ''vs.'' input voltage for a bipolar inverter with ''V<sub>CC</sub>''<nowiki>=</nowiki>5V and ''R<sub>C</sub>''<nowiki>=</nowiki>1k&Omega;.
|Amplifier input and output.PNG|Input and output signals for bipolar inverter used as an amplifier.
|Two-port with Thevenin driver.PNG| Two-port network with symbol definitions.
|Z-equivalent two-port.PNG| Z-equivalent two port showing independent variables ''I<sub>1</sub>'' and ''I<sub>2</sub>''.
|Y-equivalent two-port.PNG| Y-equivalent two port showing independent variables
|H-equivalent two-port.PNG|H-equivalent two-port showing independent variables
|G-equivalent two-port.PNG| G-equivalent two-port showing independent variables
|Block diagram asymptotic gain.PNG|Block diagram for asymptotic gain model
|Signal-flow graph for asymptotic gain model.PNG|Possible signal-flow graph for the asymptotic gain model
|MOSFET Transresistance amplifier.PNG| MOSFET transresistance feedback amplifier.
|Bipolar transresistance feedback amplifier.PNG| Collector-to-base biased bipolar amplifier.
|Shunt-series feedback amplifier.PNG|Two-transistor feedback amplifier; any source impedance ''R<sub>S</sub>'' is lumped in with the base resistor ''R<sub>B</sub>''.
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{{Gallery-mixed
|caption=Small-signal circuits
|width=200
|lines=5
|PN-diode small-signal circuit2.PNG|Small-signal circuit for ''pn-''diode driven by a current signal represented as a [[Norton's theorem|Norton source]].
|Bipolar current mirror with emitter resistors.PNG| Bipolar current mirror with emitter resistors
|Small-signal circuit for bipolar mirror.PNG| Small-signal circuit for bipolar current mirror
|Common base with current drive.PNG| Common base circuit with active load and current drive.
|Common base with current driver.PNG|Common-base amplifier with AC current source ''I<sub>1</sub>'' as signal input
|Common base with voltage drive.PNG|Bipolar transistor with base grounded and signal applied to emitter.
|Small-signal common base circuit.PNG|Common-base amplifier with AC voltage source ''V<sub>1</sub>'' as signal input
|Norton equivalent circuit.PNG|The result of applying Norton's theorem.
|Current follower.PNG|Bipolar current buffer.
|Current follower; small-signal.PNG|Small-signal circuit to find output current.
|Current follower output resistance.PNG|Small-signal circuit with test current ''i<sub>X</sub>'' to find Norton resistance.
|Thevenin equivalent circuit.PNG|The result of applying Thévenin's theorem.
|Voltage Follower.PNG|Bipolar buffer.
|Voltage Follower Small-signal.PNG|Small-signal circuit for voltage follower.
|Voltage follower output resistance.PNG|Determination of the small-signal output resistance.
|Bipolar hybrid-pi model.PNG| Simplified, low-frequency hybrid-pi [[BJT]] model.
|Bipolar hybrid-pi capacitances.PNG|Bipolar hybrid-pi model with parasitic capacitances.
|Bipolar hybrid-pi model.PNG| Simplified, low-frequency hybrid-pi [[BJT]] model.
|Bipolar hybrid-pi capacitances.PNG|Bipolar hybrid-pi model with parasitic capacitances.
|MOSFET hybrid-pi with capactances.PNG|Simplified, three-terminal MOSFET hybrid-pi model.
|MOSFET four-terminal hybrid-pi circuit.PNG|Four-terminal small-signal MOSFET circuit.
|Miller effect.PNG|Miller effect: These two circuits are equivalent.
|Small-signal transresistance amplifier.PNG| Small-signal circuit for transresistance amplifier
|Return ratio.PNG|Small-signal circuit with return path broken and test current ''i<sub>t</sub>'' driving amplifier at the break.
|Using return ratio.PNG|Three small-signal schematics used to discuss the asymptotic gain model
}}
{{Gallery-mixed
|caption=Return ratio
|width=500
|lines=5
|Inserting source for return ratio.PNG|''Left'' - small-signal circuit corresponding to bipolar amplifier; ''Center'' - inserting independent source and marking leads to be cut; ''Right''  - cutting the dependent source free and short-circuiting broken leads.
}}
{{Gallery-mixed
|caption=Amplifiers
|width=200
|lines=5
|Aspects of step response.PNG|Some terms used to describe step response in time domain.
|Negative feedback amplifier.PNG|Ideal negative feedback model; open loop gain is ''A''<sub>OL</sub> and feedback factor is β.
|Conjugate poles.PNG|Conjugate pole locations for step response of two-pole feedback amplifier.
|Step response of negative feedback amplifier.PNG| Step-response of a linear two-pole feedback amplifier.
|Overshoot control.PNG|Step response for three values of time constant ratio.
|Gain Bode plot for two-pole amplifier.PNG|Bode gain plot to find phase margin of two-pole amplifier.
|High-pass amplifier Bode plot.PNG|The Bode plot for a first-order (one-pole) [[highpass filter]]
|Low-pass amplifier Bode plot.PNG|The Bode plot for a first-order (one-pole) [[lowpass filter]]
|Bode plot for pole and zero.PNG| Bode magnitude plot for zero and for low-pass pole
|Bode phase plot for pole and zero.PNG|Bode phase plot for zero and for low-pass pole
|Superposed Bode plots for pole and zero.PNG|Bode magnitude plot for pole-zero combination; the location of the zero is ten times higher than in above figures
|Superposed Bode phase plots for pole and zero.PNG|Bode phase plot for pole-zero combination; the location of the zero is ten times higher than in above figures
|Open and closed loop gain.PNG|Gain of feedback amplifier ''A''<sub>FB</sub> in dB and corresponding open-loop amplifier ''A''<sub>OL</sub>.
|Open and closed loop phase.PNG|Phase of feedback amplifier ''°A''<sub>FB</sub> in degrees and corresponding open-loop amplifier ''°A''<sub>OL</sub>.
|Gain margin.PNG|Gain of feedback amplifier ''A''<sub>FB</sub> in dB and corresponding open-loop amplifier ''A''<sub>OL</sub>.
|Phase margin.PNG|Phase of feedback amplifier ''A''<sub>FB</sub> in degrees and corresponding open-loop amplifier ''A''<sub>OL</sub>.
|Pole splitting example.PNG| Operational amplifier with compensation capacitor ''C<sub>C</sub>'' between input and output to cause pole splitting.
|Pole splitting with Miller transformation.PNG|Operational amplifier with compensation capacitor transformed using [[Miller effect|Miller's theorem]] to replace the compensation capacitor with a Miller capacitor at the input and a frequency-dependent current source at the output.
|Two-pole Bode magnitude plot.PNG|Idealized [[Bode plot]] for a two pole amplifier design.
|Compensation capacitance.PNG|Miller capacitance at low frequencies ''C<sub>M</sub>'' (top) and compensation capacitor ''C<sub>C</sub>'' (bottom) as a function of gain

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