Circuit Lab B/C

[mdv2o5]

What is doping in the context of PN junctions and why is it done?

Answer (Click to Show Hidden Text)

Pure silicon has four valence electrons that are able to conduct electricity. Doping adjusts the concentrations of the charge carriers within the silicon crystals to either increase the number of electrons or increase the number of "holes" (aka lack of electrons). Doping with elements that have 5 valence electrons such as arsenic increases the number of electrons in the silicon crystal. This makes it "negative" or n-type. Doping with elements that have 3 valence electrons such as boron or indium creates silicon crystals that have a high concentration of holes, making it "positive" or p-type. This causes electrons to move only in one direction: from n-type to p-type. This is essentially a silicon diode. The property of allowing electrons to only flow in one direction forms the basis for more advanced transistors such as BJTs and MOSFETs.

[UTF-8 U+6211 U+662F]

What is doping in the context of PN junctions and why is it done?

Answer (Click to Show Hidden Text)

Pure silicon has four valence electrons that are able to conduct electricity. Doping adjusts the concentrations of the charge carriers within the silicon crystals to either increase the number of electrons or increase the number of "holes" (aka lack of electrons). Doping with elements that have 5 valence electrons such as arsenic increases the number of electrons in the silicon crystal. This makes it "negative" or n-type. Doping with elements that have 3 valence electrons such as boron or indium creates silicon crystals that have a high concentration of holes, making it "positive" or p-type. This causes electrons to move only in one direction: from n-type to p-type. This is essentially a silicon diode. The property of allowing electrons to only flow in one direction forms the basis for more advanced transistors such as BJTs and MOSFETs.

Yep, your turn!

[mdv2o5]

Calculate the RMS voltage of a 12V peak-to-peak sinusoidal AC signal and a 0-6V square wave with a time-on of 8ms and a period of 10 ms.

[UTF-8 U+6211 U+662F]

Calculate the RMS voltage of a 12V peak-to-peak sinusoidal AC signal and a 0-6V square wave with a time-on of 8ms and a period of 10 ms.

Click to Show Answer

[mdv2o5]

Calculate the RMS voltage of a 12V peak-to-peak sinusoidal AC signal and a 0-6V square wave with a time-on of 8ms and a period of 10 ms.

Click to Show Answer

Looks good!

[UTF-8 U+6211 U+662F]

All right! Derive an equation for the power given off by a resistor from Ohm's law.

[Jacobi]

All right! Derive an equation for the power given off by a resistor from Ohm's law.

My Answer (Click to Show Hidden Text)

By Ohm's law, [math]V = IR[/math].  By the definition of power, [math]P = VI[/math].  Thus, [math]P = (IR)I = I^2R[/math].

[UTF-8 U+6211 U+662F]

All right! Derive an equation for the power given off by a resistor from Ohm's law.

My Answer (Click to Show Hidden Text)

By Ohm's law, [math]V = IR[/math].  By the definition of power, [math]P = VI[/math].  Thus, [math]P = (IR)I = I^2R[/math].

Yep, your turn, although I was thinking of a derivation using

Definition (Click to Show Hidden Text)

[math]P = \frac{dW}{dt}[/math]

But that's a little more complicated (and equivalent).

[Jacobi]

Two resistors are combined in a circuit. First, they are combined in series. Then, they are combined in parallel. What is the equivalent single resistance of each setup?

[UTF-8 U+6211 U+662F]

Two resistors are combined in a circuit. First, they are combined in series. Then, they are combined in parallel. What is the equivalent single resistance of each setup?

Click to Show Answer