Analog ElectronicsBasic electronicsOhm’s law V=IRImpedances in seriesReq=RiImpedances in parallel1/Req = 1/RiVoltage dividerVout = Vin[R2/(R1+R2)]Application for signal sources:connection of any device with a non-zero input impedance to consequently be careful that the input impedance of the downSignal sourcesPractical signal sourcesLimitations Basically low power, low voltage, need conditionlow signal leveloutput impedancenon-linearitysaturationoffsetnoiseDealing with limitationsAmplification using operational amplifiersRules for op-amps with external feedback:1. The output attempts to do whatever is necessary to make t2. The inputs draw no current.inverting amplifierGain = -Rfeedback/RinputInput impedance = Rinputnon-inverting amplifierGain = 1 + R2/R1 (R2 is feedback resistor, R1 to ground andInput impedance is essentially infinite (10^6 to 10^8)summing amplifierUses inverting amplifier configurationMultiple input resistancesVout = -Rfeedback/Rivoltage followerimpedance matching devicedifferential amplifierinstrumentation amplifierWhat you want to use for differential measurementsdesign an amplification circuit to condition a signal to a dLimitations of op-ampslimited output voltage Vcc less ~2Vlimited output current about 15 mA maxlimitations on gain setting resistors between 1KΩ and 1 MΩComparatorsRC filterslow-pass filteroutput magnitude and phasehigh-pass filteroutput magnitude and phaseDiodes and diode circuitsDiode operationOn when forward bias is > 0.7 VRectificationLED’sLED forward bias is about 2 VTransistorsTypesBipolar NPNStarts to turn on when Vbe is >0.7 VIc = hfe*IbBipolar PNPStarts to turn on when Vbe is < 0.7 VMOSFET (enhancement or depletion types, and N or P-channel)Voltage controlled transistorVgate > Vsource to turn onVGS > 5 V on (but will depend on MOSFET)VGS < 1 V off (but will depend on MOSFET)Fundamental propertiesEquivalent circuit modelBehaviorCutoffLinearSaturationUse of the transistor as a switchUsing a signal source to control relatively large currentsDriving base hard enough to saturate transistorApplicationsDriving a relayFly-back diodeNeed to provide a path for current to flow due to induced voCharging is like pushing current through a resistor.Discharging, we get a voltage with the opposite sign.Power suppliesTransformersRectifiersRegulatorsGroundingSensors and TransducersResolutionSensor types and applicationsAdvantagesDisadvantagesPerformance characteristicsEncodersSwitchesActuators and MotorsMotor actionDC motor fundamentalsStepper motor fundamentalsServosMotor selectionSystem inertia calculationTorque requirementDigital ElectronicsBinary numbersHexadecimal numbersLogic voltage levels and interfacing for TTL and CMOSLogic gates (combinational logic)Design processBrute force approachSum-of-productsProduct-of-sumsSequential logic (flip flops, etc.)ApplicationsC ProgrammingBasics with applications for embedded microcontrollersDigital I/OAnalog to digitalA/D and D/A ConvertersBasic operation and limitationsUsing the A/D converter on the Atmega 128Interfacing MotorsInterfacing stepper motorsInterfacing DC motorsPulse width modulationH-bridgeOn-off control using transistors, motor driver chips, or relR/C servosLab experimentsHomeworkME 106 Spring 2005 Course Review Outline 1 ME 106 Spring 2005 Course Review Analog Electronics Basic electronics Ohm’s law V=IR Impedances in series Req=ΣRi Impedances in parallel 1/Req = Σ1/Ri Voltage divider Vout = Vin[R2/(R1+R2)] Application for signal sources: connection of any device with a non-zero input impedance to a practical signal source will form a voltage divider consequently be careful that the input impedance of the downstream device is significantly higher (at least 10x) than the output impedance of the signal source Signal sources Practical signal sources Limitations Basically low power, low voltage, need conditioning low signal level output impedance non-linearity saturation offset noise Dealing with limitations Amplification using operational amplifiers Rules for op-amps with external feedback: 1. The output attempts to do whatever is necessary to make the voltage difference between the inputs = 0. 2. The inputs draw no current. inverting amplifier Gain = -Rfeedback/Rinput Input impedance = Rinput non-inverting amplifier Gain = 1 + R2/R1 (R2 is feedback resistor, R1 to ground and R2) Input impedance is essentially infinite (10^6 to 10^8) summing amplifier Uses inverting amplifier configuration Multiple input resistances Vout = Σ-Rfeedback/Ri voltage follower BJ Furman me106 S05 course review.doc May 19, 2005ME 106 Spring 2005 Course Review Outline 2 impedance matching device differential amplifier instrumentation amplifier What you want to use for differential measurements design an amplification circuit to condition a signal to a desired range Limitations of op-amps limited output voltage Vcc less ~2V limited output current about 15 mA max limitations on gain setting resistors between 1KΩ and 1 MΩ Comparators RC filters low-pass filter output magnitude and phase high-pass filter output magnitude and phase Diodes and diode circuits Diode operation On when forward bias is > 0.7 V Rectification LED’s LED forward bias is about 2 V Transistors Types Bipolar NPN Starts to turn on when Vbe is >0.7 V Ic = hfe*Ib Bipolar PNP Starts to turn on when Vbe is < 0.7 V MOSFET (enhancement or depletion types, and N or P-channel) Voltage controlled transistor Vgate > Vsource to turn on VGS > 5 V on (but will depend on MOSFET) VGS < 1 V off (but will depend on MOSFET) Fundamental properties Equivalent circuit model Behavior Cutoff BJ Furman me106 S05 course review.doc May 19, 2005ME 106 Spring 2005 Course Review Outline 3 Linear Saturation Use of the transistor as a switch Using a signal source to control relatively large currents Driving base hard enough to saturate transistor Applications Driving a relay Fly-back diode Need to provide a path for current to flow due to induced voltage from sudden change in current V = Ldi/dt. Charging is like pushing current through a resistor. Discharging, we get a voltage with the opposite sign. Power supplies Transformers Rectifiers Regulators Grounding Sensors and Transducers Resolution Sensor types and applications Advantages Disadvantages Performance characteristics Encoders Switches Actuators and Motors Motor action DC motor fundamentals Stepper motor fundamentals Servos Motor selection System inertia calculation Torque