Virtual Skill testing + Virtual Laboratory Experience + Links to Top Theory Sites = Best Free Online VLS.
I provide a reading list for each topic that a student can use to learn the relevant subject matter. This site and my virtual electronics kits test your electronics skill. My digital simulations create screens of data in binary format that show the status of my virtual computer and many digital circuits.

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Lecture Text Capacitive RC Circuits
Troubleshooting RC circuits. I rarely stopped probing a circuits that I was troubleshooting to do calculations with pencil and paper. The one exception to this rule was that I frequently used this slide rule calculator to calculate the impedance of a capacitor or inductor. This handy slide rule calculator made it easy for me to calculate the reactance of coils and capacitors at a particular frequency. Today these slide rules may be collectors items. I have provided you with a link to online calculators of impedance and resonant frequency. See link below. I have also provided links to a few of my circuit animations. Those of you who read and performed troubleshooting exercises in my ebook, "Electronic Concepts" may find these animations redundant. You don't have to use the online calculator if you have a programmable calculator that you can use to execute any formula or sequence of formulas you desire. I consider JavaScript the official program for this site and I teach it on my JavaScript site. JavaScript is available on most Computers and can be developed with Note Pad and with Microsoft Internet Explorer. Of course a JavaScript development platform is also available on Netscape. Once you calculate the impedance of a capacitor in ohms for a particular frequency, you will be able the view circuits and voltage dividers in terms of components measured in ohms. Of course we must consider the phasor nature of the components. Thus, the sum of a 10 ohm capacitance reactance in series with 10 ohm resistor is simply their vector sum (14.14). The impedance of a ten ohm resistor in series with a 10 ohm resistor would have been 20 ohm. In the case of a 10 ohm capacitor reactance and 10 ohm resistor in parallel, we can use conductance to analyze the circuit . Conductance is the reciprocal of resistance. The reciprocal of 10 is .1. The vector sum of the resistor conductance and the capacitor conductance is .1414 . The reciprocal of .1414 is 7.07 . Thus the total impedance of the 10 ohm resistance and the 10 ohm capacitance reactance in parallel is 7.07 ohms rather than the 5.0 ohms that two 10 ohm resistors in parallel would produce. Of course you could use the Pythagorean theorem to calculate the series impedance of any pair of reactance's. When we study transistor amplifiers in later lessons, you will see that a resistor and capacitor in parallel are used in transistor emitter circuits to effect the frequency response of the amplifiers. I have created circuit animations of amplifiers that illustrate this. (Check links at bottom of page.) A resistor and capacitor in series also makes a simple inexpensive high pass or low pass filter. Troubleshooting circuit failures. Circuits usually fail in a manner that causes a significant change in performance. Thus, if you only have a rough estimate of how a circuit should perform, the deviation caused by the failure of a resistor or a capacitor is usually quit noticeable to a troubleshooter. Therefore, rough approximations of circuit performance (made in ones head) are often all that is required for troubleshooting a circuit.

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