Don’t just sit there! Build something!!Learning to mathematically analyze circuits requires much study and practice. Typically, students practice by working through lots of sample problems and checking their answers against those provided by the textbook or the instructor. While this is good, there is a much better way.You will learn much more by actually building and analyzing real circuits, letting your test equipment provide the “answers” instead of a book or another person.

• Calculer Ses Circuits Pdf Converter Pdf

Notes:It has been my experience that students require much practice with circuit analysis to become proficient. To this end, instructors usually provide their students with lots of practice problems to work through, and provide answers for students to check their work against. While this approach makes students proficient in circuit theory, it fails to fully educate them.Students don’t just need mathematical practice.

They also need real, hands-on practice building circuits and using test equipment. So, I suggest the following alternative approach: students should build their own “practice problems” with real components, and try to mathematically predict the various voltage and current values. This way, the mathematical theory “comes alive,” and students gain practical proficiency they wouldn’t gain merely by solving equations.Another reason for following this method of practice is to teach students scientific method: the process of testing a hypothesis (in this case, mathematical predictions) by performing a real experiment. Students will also develop real troubleshooting skills as they occasionally make circuit construction errors.Spend a few moments of time with your class to review some of the “rules” for building circuits before they begin. Discuss these issues with your students in the same Socratic manner you would normally discuss the worksheet questions, rather than simply telling them what they should and should not do. I never cease to be amazed at how poorly students grasp instructions when presented in a typical lecture (instructor monologue) format!A note to those instructors who may complain about the “wasted” time required to have students build real circuits instead of just mathematically analyzing theoretical circuits:What is the purpose of students taking your course?If your students will be working with real circuits, then they should learn on real circuits whenever possible. If your goal is to educate theoretical physicists, then stick with abstract analysis, by all means!

But most of us plan for our students to do something in the real world with the education we give them. The “wasted” time spent building real circuits will pay huge dividends when it comes time for them to apply their knowledge to practical problems.Furthermore, having students build their own practice problems teaches them how to perform primary research, thus empowering them to continue their electrical/electronics education autonomously.In most sciences, realistic experiments are much more difficult and expensive to set up than electrical circuits. Nuclear physics, biology, geology, and chemistry professors would just love to be able to have their students apply advanced mathematics to real experiments posing no safety hazard and costing less than a textbook. They can’t, but you can.

Exploit the convenience inherent to your science, and get those students of yours practicing their math on lots of real circuits! This circuit uses an 8038 waveform generator IC (integrated circuit) to produce a “sawtooth” waveform, which is then compared against a variable DC voltage from a potentiometer:The result is a pulse waveform to the base of the power transistor, of the same frequency as the sawtooth waveform. Normally in circuits such as this, the frequency is at least several hundred Hertz.Explain what happens to the brightness of the lamp when the potentiometer wiper is moved closer to +V, and when it is moved closer to ground.

The schematic diagram shown here is for a “buck” converter circuit, a type of DC-DC “switching” power conversion circuit:In this circuit, the transistor is either fully on or fully off; that is, driven between the extremes of saturation or cutoff. By avoiding the transistor’s “active” mode (where it would drop substantial voltage while conducting current), very low transistor power dissipations can be achieved. With little power wasted in the form of heat, “switching” power conversion circuits are typically very efficient.Trace all current directions during both states of the transistor. Also, mark the inductor’s voltage polarity during both states of the transistor.

The schematic diagram shown here is for a “boost” converter circuit, a type of DC-DC “switching” power conversion circuit:In this circuit, the transistor is either fully on or fully off; that is, driven between the extremes of saturation or cutoff. By avoiding the transistor’s “active” mode (where it would drop substantial voltage while conducting current), very low transistor power dissipations can be achieved. With little power wasted in the form of heat, “switching” power conversion circuits are typically very efficient.Trace all current directions during both states of the transistor.

Calculer Ses Circuits Pdf Converter Pdf

Also, mark the inductor’s voltage polarity during both states of the transistor. The schematic diagram shown here is for an “inverting” converter circuit, a type of DC-DC “switching” power conversion circuit:In this circuit, the transistor is either fully on or fully off; that is, driven between the extremes of saturation or cutoff. By avoiding the transistor’s “active” mode (where it would drop substantial voltage while conducting current), very low transistor power dissipations can be achieved.

With little power wasted in the form of heat, switching” power conversion circuits are typically very efficient.Trace all current directions during both states of the transistor. Also, mark the inductor’s voltage polarity during both states of the transistor. The schematic diagram shown here is for a “Cuk” converter circuit, a type of DC-DC “switching” power conversion circuit:In this circuit, the transistor is either fully on or fully off; that is, driven between the extremes of saturation or cutoff. By avoiding the transistor’s “active” mode (where it would drop substantial voltage while conducting current), very low transistor power dissipations can be achieved. With little power wasted in the form of heat, “switching” power conversion circuits are typically very efficient.Trace all current directions during both states of the transistor. Also, mark the both inductors’ voltage polarities during both states of the transistor.

Drive circuit fails with a constant “low” (0 volts) output signal: Output voltage rises to become approximately equal to V in. Drive circuit fails with a constant “high” (+V) output signal: Output voltage falls to zero after capacitor discharges. Diode fails shorted: Output voltage exhibits very large “ripple” as the voltage repeatedly falls to zero and spikes back up each drive cycle, transistor may fail due to overheating. Inductor fails open: Output voltage falls to zero after capacitor discharges. Capacitor fails shorted: Output voltage falls to zero immediately.

So-called linear regulator circuits work by adjusting either a series resistance or a shunt resistance to maintain output voltage at some fractional value of input voltage:Typically, these variable resistances are provided by transistors rather than actual rheostats, which would have to be manually controlled.Explain why a switching regulator circuit would perform the same task as a linear regulator circuit at a much greater efficiency. Also, identify which type(s) of switching regulator circuit would be best suited for the task of reducing an input voltage to a lesser output voltage. Notes:In the process of analyzing switching regulator functionality, it is easy for students to overlook the purpose for why they exist at all. Discuss the importance of power conversion efficiency, especially for electronic applications that are battery powered.An important point to emphasize in this question is that most of the switching “regulator” circuits first shown to students are not actually regulators at all, but merely converters.

A switching converter circuit does not become a regulator circuit until a feedback control is added. Such controls are usually too complex to introduce at the very beginning, so they are typically omitted for simplicity’s sake. However, students should realize the difference between a switching regulator circuit and a mere switching converter circuit, lest they believe the converter to be capable of more than it is. Notes:Explain to your students that switching power conversion circuits are very efficient: typically 85 to 95 percent! It should be rather obvious which battery will last longer, and why. This is precisely why switching regulator circuits (DC-DC converters with a feedback network to stabilize output voltage) are used in place of linear regulator circuits (zener diode based) in many battery-powered electronic applications.In essence, switching converter circuits act like DC transformers, able to step voltage down (or up), with current inversely proportional. Of course, the Law of Energy Conservation holds for switching circuits just as it does for transformers, and students may find this Law the easiest way to perform supply/load current calculations knowing the supply and load voltages:P out ≈ P inV inI in ≈ V outI outIf time permits, you might want to show your students a datasheet for a power converter controller, showing them how integrated circuits exist to precisely control the switching of s for power converter circuits just like this.

The output voltage of a Cuk converter circuit (named after the engineer who invented it) is a function of the input voltage and the duty cycle of the switching signal, represented by the variable D (ranging in value from 0% to 100%), where D = (t on)/(t on + t off):Based on this mathematical relationship, calculate the output voltage of this converter circuit at these duty cycles, assuming an input voltage of 25 volts: D = 0%; V out = D = 25%; V out = D = 50%; V out = D = 75%; V out = D = 100%; V out =. Notes:The calculations for this circuit should be straightforward, except for the last calculation with a duty cycle of D = 100%.

Here, students must take a close look at the circuit and not just follow the formula blindly.Note that the switching element in the schematic diagram is shown in generic form. It would never be a mechanical switch, but rather a transistor of some kind.Astute students will note that there is no difference between the standard inverting converter circuit and the Cuk design, as far as output voltage calculations are concerned. This, however, does not mean the two circuits are equivalent in all ways!

One definite advantage of the Cuk converter over the standard inverting converter is that the Cuk’s input current never goes to zero during the switch’s “off” cycle. This makes the Cuk circuit a “quieter” load as seen from the power source.

Both inverting and buck converter circuits create a lot of electrical noise on the supply side if their inputs are unfiltered! Notes:Given the equations for these converter circuit types solving for output voltage in terms of input voltage and duty cycle D, this question is nothing more than an exercise in algebraic manipulation.Note to your students that all of these equations assume a condition of zero load on the converter circuit.

When loads are present, of course, the output voltage will not be the same as what is predicted by these neat, simple formulae. Although these DC-DC power converter circuits are commonly referred to as “regulators,” it is somewhat misleading to do so because it falsely implies a capacity for self-correction of output voltage. Only when coupled to a feedback control network are any of these converter circuits capable of actually regulating output voltage to a set value. Notes:Calculations involving energy efficiency seem very confusing to some students.

One principle that I often remind my students of is the Law of Energy Conservation, which prohibits any circuit from outputting more energy (or power) than it takes in. All too often, students mis-calculate in problems such as these, ending up with output powers greater than input powers!Discuss problem-solving techniques, soliciting input from your students.

Ideally, have individuals or groups present their techniques to the class as a whole, so you may observe their thinking processes and so that other students may learn how to become better problem-solvers. Notes:Calculations involving energy efficiency seem very confusing to some students. One principle that I often remind my students of is the Law of Energy Conservation, which prohibits any circuit from outputting more energy (or power) than it takes in. All too often, students mis-calculate in problems such as these, ending up with output powers greater than input powers!Discuss problem-solving techniques, soliciting input from your students. Ideally, have individuals or groups present their techniques to the class as a whole, so you may observe their thinking processes and so that other students may learn how to become better problem-solvers.

Notes:Calculations involving energy efficiency seem very confusing to some students. One principle that I often remind my students of is the Law of Energy Conservation, which prohibits any circuit from outputting more energy (or power) than it takes in. All too often, students mis-calculate in problems such as these, ending up with output powers greater than input powers!Discuss problem-solving techniques, soliciting input from your students. Ideally, have individuals or groups present their techniques to the class as a whole, so you may observe their thinking processes and so that other students may learn how to become better problem-solvers. Notes:Here, students see a PWM control circuit coupled with a buck converter to provide voltage-regulated power conversion.

Ask them what form of feedback (positive or negative?) is used in this circuit to regulate the output voltage at a steady value.Let your students know that the PWM and feedback functions for switching regulator circuits are often provided in a single, application-specific integrated circuit rather than by a collection of discrete components and IC’s as shown in the question. While simple “brute-force” AC-DC power supply circuits (transformer, rectifier, filter, regulator) are still used in a variety of electronic equipment, another form of power supply is more prevalent in systems where small size and efficiency are design requirements.

This type of power supply is called a switching power supply.Explain what a “switching power supply” is, and provide a schematic diagram of one for presentation and discussion. (Hint: most electronic computers use “switching” power supplies instead of “brute force” power supplies, so schematic diagrams should not be difficult to find.).

Notes:While many “switching” power supply circuits will be too complex for beginning electronics students to fully understand, it will still be a useful exercise to analyze such a schematic and identify the major components (and functions).Ask your students why “switching” power supplies are smaller and more efficient than “brute force” designs. Ask your students to note the type of transformer used in switching power supplies, and contrast its construction to that of line-frequency power transformers.

Suppose a friend of yours recently purchased an off-road vehicle. This friend also purchased a military-surplus spotlight, which he thinks would be a great accessory for off-road illumination at night.

The only problem is, the spotlight is rated for 24 volts, while the electrical system in his vehicle is 12 volt.Your friend asks you to engineer a solution for powering the 24-volt spotlight with the 12 volts available on his vehicle. Of course, you are not allowed to modify the vehicle’s electrical system (change it to 24 volt generator, battery, starter motor, etc.), because it is new and still under warranty. What do you recommend to your friend?Draw a component-level schematic diagram of your solution to this problem. Notes:Students may be inclined to give easy answers to this problem (“use a DC-DC converter!”), but the purpose of it is for students to explore solutions at the component level. Even if they do not yet understand how the circuitry works, they should be able to find complete solutions in their research, or at least enough schematics for sections of the conversion process for them to engineer a complete solution.Remind your students that this is a powerful spotlight they’re going to have to power!

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Their conversion system may have to handle hundreds of watts. ∫f(x) dx Calculus alert!Electronic power conversion circuits known as inverters convert DC into AC by using transistor switching elements to periodically reverse the polarity of the DC voltage. Usually, inverters also increase the voltage level of the input power by applying the switched-DC voltage to the primary winding of a step-up transformer.

You may think of an inverter’s switching electronics as akin to double-pole, double-throw switch being flipped back and forth many times per second:The first commercially available inverters produced simple square-wave output:However, this caused problems for most power transformers designed to operate on sine-wave AC power. When powered by the square-wave output of such an inverter, most transformers would saturate due to excessive magnetic flux accumulating in the core at certain points of the waveform’s cycle. A common topology for DC-AC power converter circuits uses a pair of transistors to switch DC current through the center-tapped winding of a step-up transformer, like this:In order for this form of circuit to function properly, the transistor “firing” signals must be precisely synchronized to ensure the two are never turned on simultaneously.

The following schematic diagram shows a circuit to generate the necessary signals:Explain how this circuit works, and identify the locations of the frequency control and pulse duty-cycle control potentiometers. A timing diagram is worth a thousand words:. V ref = DC reference voltage set by duty cycle potentiometer. V cap = Voltage measured at top terminal of the 555’s capacitor.

V comp = Comparator output voltage. V 555(out) = 555 timer output voltage. Q = Noninverted output of J-K flip-flop. Q = Inverted output of J-K flip-flopFollow-up question: which direction would you have to move the frequency potentiometer to increase the output frequency of this circuit? Which direction would you have to move the duty cycle potentiometer to increase that as well?Challenge question: suppose you were prototyping this circuit without the benefit of an oscilloscope. How could you test the circuit to ensure the final output pulses to the transistors are never simultaneously in the “high” logic state? Assume you had a parts assortment complete with light-emitting diodes and other passive components.