Analog Power Raiser is an Analog Computer that raises one input signal to the power of another input signal. How does this Analog computer work? What are the roles of its subcircuits and circuit components? This unique circuit is designed, presented and analyzed here as my 200th circuit video in my analog circuits playlist • Electrical Engineering... . This interesting analog circuit is designed with nine operational amplifiers, eight NPN BJT Bipolar Junction Transistors, two 1k ohm PTC TempCo resistors with positive temperature coefficients and two potentiometers to compute V1^V2 utilizing a smart technique of computing exp(V2*log(V1)) where exp() is the Antilog function (AntiLog Amplifier). V1 and V2 are the input voltage signals in this circuit and Vo=V1^V2 is the output voltage of the circuit. As discussed in detail in this video, this unique circuit uses Shockley PN junction equation Vbe=VT*log(collectorCurrent/SaturationCurrent) and matched pair of PN junctions of BJT transistors to remove the dependency on saturation current that is exponentially dependent on silicon process and junction temperature. Circuit also uses PTC Temperature Compensating resistor PT146 to then compensate the linear dependency on temperature to a good extent. The first subcircuit has two op amps and a pair of matched NPN BJT transistors to function as a Log Amplifier to compute natural logarithm of one input signal. Then the second subcircuit functions as a four-quadrant analog multiplier to compute the product of V2 and Log(V1) to generate V2*Log(V1) which is then fed as input to the third subcircuit that finally computes the antilog or Exp(V2*Log(V1)) = V1^V2 as the final output voltage of this unique Analog computer.
21 фев 2024
