In place of the multimeter used in the first part of lab, the oscilloscope will be used. The voltage on a charging and discharging capacitor through a reversebiased diode is calculated from basic equations and. In this experiment, you will work with a circuit where a resistor is combined in series with a capacitor. In this laboratory you have observed the charging and discharging behavior of a rc circuit. A capacitor consists of two small metal plates that are separated by a small distance. Equipment 1 function generator pc scope software 1 digital multimeter and leads 1 decade resistance box 1 capacitor nominally 0. This experiment will introduce you to the properties of circuits that contain both resistors and capacitors. The purpose of this experiment is to study the behavior of the current and voltages in an. To study the transient behavior of voltage and current in rc circuits. As with all electrical circuits, connect up the components of the circuit first, then introduce the measuring equipment in this case the oscilloscope only afterwards. The assignment draws from chapters 610 of your text.
Rc circuits 4 of 8 charging a capacitor, time constant, voltage. The rules for series and parallel combinations of resistors and. Turn the power supply control knob clockwise until the voltage across the capacitor and resistor is approximately 10 volts, as indicated on the multimeter. This experiment features an rc circuit, which is one of the simplest circuits that uses a capacitor. Rc circuits abstract abstract the purpose of the rc. However, since we have swapped the resistor and the capacitor, the grounds are at the same point in the circuit.
In this experiment, this input voltage is read by the oscilloscopes ch 1. To experimentally determine the resonance frequency in a series rlc circuit and compare this to the expected resonance value. Build the following circuit using two resistors that have different resistance, one about twice the resistance of the other. Kirchoffs laws will be stated, and used to find the currents in a circuit. The rc circuit department of physics and astronomy. Turn on the variable power supply and turn it up to 6 volts. The document presented the main theories, as well as many experiments for verification of various theoretical and. The inductor is based on the principle of inductance that moving charges create a magnetic eld the reverse is also true a moving magnetic eld creates an electric eld. Rc filter networks lab report robert clancy 04329741 december 8, 2005 abstract the aims of this experiment are to examine rc circuits as lowpass and highpass lters to source voltages of sinusoidal and square wave signals. Rc circuits introduction capacitors are used in timing circuits in many devices. Rc and rl circuits page 1 rc and rl circuits rc circuits in this lab we study a simple circuit with a resistor and a capacitor from two points of view, one in time and the other in frequency. Compare the nature of the voltage versus time graph and current versus time graph while charging and discharging. Also to study the transient decay of an initial charge on a capacitor through a resistor.
The pulsewidth relative to a circuit s time constant determines how it is affected by an rc circuit. Discussion of principles a capacitor consists of two conductors separated by a small distance. To learn how to display and interpret signals and circuit outputs using features of datastudio. In this lab, we will study the behavior of capacitors while we add or remove charge from the plates.
Lab period low pass and high pass filters parts required for this lab. When the switch is moves to position, the input voltage drops to zero. Thus, you are measuring the voltage of the resistor in an rc circuit. Ee 43100 rc circuits 1 experiment guide for rc circuits i. In this experiment, charging and discharging of the capacitor with different resistors were observed. To understand the time constant in an rc circuit and how it can be changed. R is the circuit resistance your dome light in this. The current in the circuit while the capacitor is charging is described as an exponential decay function e r v i t 0trc 2 where the quantity rc resistance. In the lecture, we talked about a simple, idealized kind of capacitor, a parallel plate capacitor, which consists of two metal sheets. Rc and lr time constants charging and discharging circuit schematic diagram illustration of the experiment experiment instructions measuring voltage of your circuit.
This book presents the fundamentals of electronic and electrical circuits. The circuits will be wired up on the pasco circuit board. A tutorial and multisim simulation on the rc time constant stem videos for the flipped classroom. To examine the response to different timevarying voltages of a. This circuit provides a dc voltage of v dd2 at the output. The charging and discharging of a capacitor is the actual movement of electrons into and out of the capacitor. Series rc circuit in a series rc circuit, since the currents are the same then the voltages across r and c are 90 o out of phase.
In todays lab youll be using a new circuit element called a. To study resonance in an rlc circuit by examining the current through the circuit as a function of the frequency of the applied voltage. Although we wont touch on it in this lab, rc circuits form the. To measure the time constants associated with a discharging and charging rc resistive. Lab 5 physics 212 lab rc circuits introduction the manner by which the which the voltage on a capacitor increases or decreases is studied. The equation shows that the rc circuit is an approximate. Pdf in this experiment, a capacitor was charged to its full capacitance then discharged through a resistor.
To measure the time constants associated with a discharging and charging rc. Guidelines for the plots see the example on the right 1 always use the scatter plot. Experiment5 c 3 c 2 c 1 q q q v v 1 v 2 v 3 figure 7. A schematic representation of three capacitors in series. The voltage through an rlc series circuit will be measured as a function of frequency for a fixed applied voltage. Pdf calculating the time constant of an rc circuit researchgate. Ac circuit experiment this lab deals with circuits involving resistors, capacitors and inductors in which the currents and voltages vary sinusoidally in time. A measure of time required for certain changes in voltages and currents in rc and rl circuits. Rc circuits in this presentation, circuits with multiple batteries, resistors and capacitors will be reduced to an equivalent system with a single battery, a single resistor, and a single capacitor. This lab covers the basic characteristics of rc circuits, including both dc and ac analysis, simulation, and experimentation. Rc circuits and the oscilloscope physics lab x objective in this series of experiments, the time constant of an rc circuit will be measured experimentally and compared with the theoretical expression for it.
This is commonly known as an rc circuit and is used often in electronic timing circuits. So we were able to verify the capacitance for all the parts of experiment one. The time that your dome lights inside your car stay on after you turn o your cars ignition at night is one example of how a capacitor can be used to. Capacitors a capacitor is a passive electronic component that stores energy in the form of an electrostatic field. The function of a capacitor is to obtain, hold, and store charge, especially in the case of short. The purpose of this lab session is to examine how a capacitor stores its electric charge and how it discharges by producing a current through a resistor. To extend the charging process, the resistors were used.
Suppose we connect a battery, with voltage, across a resistor and capacitor in series as shown by figure 3. Theoretically, the time constant is given by the product of the resistance and capacitance in the circuit, rc. For this, the circuit that we used included the resistor and the capacitor with the power supply. The purpose of this lab is to experiment with building an rc circuit using a breadboard. Chapter 32b rc circuits a powerpoint presentation by paul e. The value we use to characterize these kinds of circuits is given by the time constant defined as. This experiment is an introduction to the wiring of simple electrical circuits, the use of ammeters and voltmeters, series and parallel circuits, and rc circuits.
The beauty of a diode lies in its voltagedependent nonlinear resistance. The series rc circuit and the oscilloscope we shall use the oscilloscope to study charging and discharging of a capacitor in a simple rc circuit similar to the one shown in fig. Rc rlc filters and labview description and background in this lab you will a manipulate instruments manually to determine the inputoutput characteristics of an rc filter, and then b use an instrument control system called labview made by national instruments, inc. Circuits figure 1 shows the firstorder rc circuit whose step response will be studied in this lab. Turn on the power supply with the control knob fully counterclockwise zero. You will study this circuit and ways to change its effective capacitance by combining capacitors in series and parallel arrangements. In this experiment, we apply a pulse waveform to the rc circuit to analyse the transient response of the circuit. Lab 7 lr circuits introduction the english physicist michael faraday found in 1831 that when the current through a coil changes, the coil produces a changing magnetic field in addition to the field of the changing current, which induces an electromotive force emf in the coil itself. Remember from lecture that capacitors are devices which store charge.
Figure 1 shows the firstorder rc circuit whose step response will be studied in this lab. The time constant is the amount fi rc i i k q of time an rc circuit takes to discharge a capacitor to about. Function generator 1 function generator 2 red test lead red test lead. Rc circuits california state university, fullerton. Determine the time constant of a circuit through simulation, experiment, and analytically. Given a capacitor starting with q given a capacitor starting with no charge, the time constant is the amount of time an rc circuit takes to charge a capacitor to about 63% of its t final value. An rc circuit is simply a circuit with a voltage source connected in series with a resistor and a capacitor. Most students complete part a in week one and part b in week two. A tutorial and multisim simulation on the rc time constant.
Rc time constant experiment downloadable pdf file yumpu. Rc circuits goals to appreciate the capacitor as a charge storage device. When the switch in figure 3 is in position, the input voltage is the peak voltage is. Construct an rc high pass filter as shown in figure 2. To measure the voltage across a capacitor as it discharges through a resistor, and to compare the result with the expected, theoretical behavior.
For the rc circuit with two capacitor in series and the rc circuit with two capacitors in parallel, percent differences between the observed and theoretical values were all 9. When the switch is moved to position, the battery is connected to the circuit and a timevarying current begins flowing through the circuit as the capacitor charges. Inductors and capacitors are energy storage devices. Rc, rl and rlc circuits y you have just determined this circuit s time constant from the capacitor discharging curve. The circuit used to couple sound into your arduinois a simple rc circuit. Be careful when measuring the voltage of the different elements in your. Not only should this lab help you understand simple rc resistorcapacitor circuits and transient signals in electronic systems, it should also help you appreciate a wide variety of mechanical systems which are analogous to rc circuits.
The viewpoint in time is based on a differential equation. Introduction this laboratory is about verifying the transient behavior of rc and rl circuits. Step response of rc circuits university of washington. If the capacitance in the circuit is doubled, how is the halflife affected. This is an explanation of how to connect the circuit of the eighth lab s experiment in physics lab 2. In place of the multimeter used in the first part of lab, the oscilloscope will be used to measure the voltage across the capacitor. Build the charging circuit and measure voltage across the capacitor when the switch is closed. Time constant of an rc circuit objective to show that the theoretical curves we derive in class for the charging and discharging of a capacitor actually apply to the real world. Their responses to di erent frequencies are investigated and the half power point is measured. Students will learn about the equations that govern capacitor charging and discharging, the rc circuit time constant, and be introduced to using rc circuits as lowpass and highpass filters.
For ac sound signals, the capacitor will block low frequencies but pass high frequencies. Retrieve a power cord and a voltage sensor from the wire rack hanging on the wall in the lab room. Show that the capacitive time constant rc has units of seconds. Rc circuits 3 figure 5 also records the voltage over the resistor. Abstract the purpose of the rc circuits lab was to study and become familiar with the method of a rc circuit while using an oscilloscope. In result, we saw that as capacitor was being charged we saw an increase in the. Tippens, professor of physics southern polytechnic state university a powerpoint presentation by. Objective in this exercise, the dc steady state response of simple rl and rc circuits is examined. The experiment connect the signal generator in series with the resistor and capacitor as shown in figure 5.
The student will measure the circuit current, the voltages across the resistor and the generator. After the file opens, there should be a graph of voltage vs time displayed. The halflife for the decay is measured directly and also calculated using the capacitive time constant. In setting up the apparatus, you first should record data for a single 100. To study the transient response in storing an electrical charge on a capacitor in an rc circuit. Rc transient circuits objectives understand rc transient circuits. Experiment 10 rlc series circuit resonance in an rlc series circuit objective. To investigate ohms law and to determine the resistance of a resistor. When a capacitor is charged through a resistor by a dc voltage source, the charge in the capacitor and the voltage across the capacitor will increase with time. It was seen in this experiment that a capacitor can be charged up to the point where its voltage is the same as the voltage across. Experiment 5 transient response of an rc circuit aims. They differ in that a capacitor stores energy as accumulated charge voltage potential and an inductor stores energy in a magnetic field that is due to.
Lessons in electric circuits, volume 1, chapter 16. Lab on rc and rl circuits substitute for uncovering a. To describe how a capacitor charges and discharges through a resistor as a function of time. This lab is concerned with the characteristics of capacitors, and circuits consisting of a resistor and a capacitor in series. To explore the time dependent behavior of rc and rl circuits pre lab reading introduction when a battery is connected to a circuit consisting of wires and other circuit elements. Under file, select open experiment, choose the file folder named capstoneactivities, and then select the rc circuit activity. Pdf theory and experiment on charging and discharging a. The current that flows in the circuit is equal to the derivative with respect to time of the capacitor charge. You need to revise the natural and step response of rc and rl circuits you have covered in lectures. Schematic diagram of rc circuit for a charging and b discharging of the capacitor 1.
A parallelplate capacitor, formed by two flat plates of area a. In place of the multimeter used in the first part of lab. Conclusion in this experiment charging and discharging of. In this experiment, you will work with a circuit where a resistor is. Rc circuits laboratory manual page 2 of 11 3 prelab exercises 3.
You will measure the voltage across the capacitor as it charges and. The transient behavior of rc circuits is also tested. Rc circuits and the oscilloscope mercer university. In our experiment we used a square wave from the signal generator as our on and off switch and the. Lab on rc and rl circuits substitute for uncovering a hidden rcl series circuit purpose. Conclusion discussion at the center of this experiment was. Lab217 rc circuits samuel dzifanu lab 217 rc circuits. In the previous two labs youve dealt strictly with resistors. Figure 2 shows two sections of the firstorder rc circuit connected in series to illustrate a simple technique to model computer bus systems pci bus, scsi bus, etc. Since charge is conserved, it can only move from the plate of one capacitor to the connected plate of the. Rlc series circuit introduction the objective of this experiment is to study the behavior of an rlc series circuit subject to an ac input voltage.
A capacitor is a passive electronic component that stores energy in the form of an electrostatic field. To observe and analyze the voltage as a function of time across a capacitor in a circuit containing a resistor and capacitor connected in series. The rc circuit 1 university of north carolina 74 part 2. Ac circuits rlc circuit introduction an inductor l is an important component of circuits, on the same level as resistors r and capacitors c. Theory overview the dc steady state response of rl and rc circuits are essential opposite of each. For ac signals, the two resistors are in parallel, so the equivalent circuit is shown on. In this experiment, you are asked to measure the time constants for the three rc circuits described above in experiment overview. Very carefully insert voltage sensor into analog input a.