LEARNING BY APPLICATION FIND THEVENIN EQUIVALENT FOR THE

LEARNING BY APPLICATION FIND THEVENIN EQUIVALENT FOR THE UNKNOWN ELEMENT USING A RESISTOR AND A VOLTMETER EQUIVALENT FOR ELEMENT+SOURCE MEASURED ACROSS TEST RESISTOR

DESIGN EXAMPLE Possible Circuit Implement the fine/coarse adjustment • Sum of terms suggests superposition • gains less than one suggest voltage divider Circuits for superposition INFINITE POSSIBLE SOLUTIONS. USE OTHER CRITERIA PLUS ENGINEERING JUDGMENT DESIGN EQUATIONS 2 EQS AND THREE UNKNOWNS!

DESIGN EXAMPLE DESIGN AN ATTENUATOR PAD DESIGN EQUATIONS SOLVING THE EQUATIONS YIELDS Analysis of Solution • requires special, high accuracy resistors • small resistance may imply large power dissipated • may require large power rating to avoid heating

DESIGN EXAMPLE DESIGN A CIRCUIT TO REALIZE THE EQUATION ANALYSIS OF THE REQUIREMENTS • sum of voltage and current • gains larger than one • inverting ANALYSIS OF PROPOSED CIRCUIT Proposed solution ANALYSIS OF SOLUTION • 2 k is standard resistor • 667 is 1 k||2 k • uses standard components! OTHER METHODS • superposition • Norton (see book)

DESIGN EXAMPLE USE A SERIES RESISTOR WITH EACH FAN TO SENSE CURRENT PROVIDE AN INDICATION OF TOTAL AIRFLOW CONSTRAINTS • VOLTAGE DROP ON SENSING RESISTOR CANNOT EXCEED 2% OF NOMINAL 24 V FAN VOLTAGE • 1 V = 50 CFM FOR THE INDICATOR Design of sensor Design of Indicator Adder inverter Inverter DESIGN EQUATIONS!

LEARNING BY DESIGN CURRENT OVERLOAD SENSOR THIS POINT MUST GO HIGH WHEN CURRENT EXCEEDS 9 A

LEARNING BY DESIGN GENERATES Vref AND ISOLATES VOLTAGE DIVIDER Analyzing circuit using superposition