Lab 5 AC Concepts and Measurements II: Capacitors and RC Time-Constant
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Time Constant of an Rc Circuit
ECGR 2155 Instrumentation and Networks Laboratory UNIVERSITY OF NORTH CAROLINA AT CHARLOTTE Department of Electrical and Computer Engineering EXPERIMENT 10 – TIME CONSTANT OF AN RC CIRCUIT OBJECTIVES The purpose of this experiment is to measure the time constant of an RC circuit experimentally and to verify the results against the values obtained by theoretical calculations. MATERIALS/EQUIPMENT NEEDED Digital Multimeter DC Power Supply Alligator (Clips) Jumper Resistor: 20kΩ Capacitor: 2,200 µF (rating = 50V or more) INTRODUCTION The time constant of RC circuits are used extensively in electronics for timing (setting oscillator frequencies, adjusting delays, blinking lights, etc.). It is necessary to understand how RC circuits behave in order to analyze and design timing circuits. In the circuit of Figure 10-1 with the switch open, the capacitor is initially uncharged, and so has a voltage, Vc, equal to 0 volts. When the single-pole single-throw (SPST) switch is closed, current begins to flow, and the capacitor begins to accumulate stored charge. Since Q=CV, as stored charge (Q) increases the capacitor voltage (Vc) increases. However, the growth of capacitor voltage is not linear; in fact it is an exponential growth. The formula which gives the instantaneous voltage across the capacitor as a function of time is (−t ) VV=1 − eτ cS Figure 10-1 Series RC Circuit EXPERIMENT 10 – TIME CONSTANT OF AN RC CIRCUIT 1 ECGR 2155 Instrumentation and Networks Laboratory This formula describes exponential growth, in which the capacitor is initially 0 volts, and grows to a value of near Vs after a finite amount of time. -
The Accuracy Comparison of Oscilloscope and Voltmeter Utilizated in Getting Dielectric Constant Values
Proceeding The 1st IBSC: Towards The Extended Use Of Basic Science For Enhancing Health, Environment, Energy And Biotechnology 211 ISBN: 978-602-60569-5-5 The Accuracy Comparison of Oscilloscope and Voltmeter Utilizated in Getting Dielectric Constant Values Bowo Eko Cahyono1, Misto1, Rofiatun1 1 Physics Departement of MIPA Faculty, Jember University, Jember – Indonesia, e-mail: [email protected] Abstract— Parallel plate capacitor is widely used as a sensor for many purposes. Researches which have used parallel plate capacitor were investigation of dielectric properties of soil in various temperature [1], characterization if cement’s dielectric [2], and measuring the dielectric constant of material in various thickness [3]. In the investigation the changing of dielectric constant, indirect method can be applied to get the dielectric constant number by measuring the voltage of input and output of the utilized circuit [4]. Oscilloscope is able to measure the voltage value although the common tool for that measurement is voltmeter. This research aims to investigate the accuracy of voltage measurement by using oscilloscope and voltmeter which leads to the accuracy of values of dielectric constant. The experiment is carried out by an electric circuit consisting of ceramic capacitor and sensor of parallel plate capacitor, function generator as a current source, oscilloscope, and voltmeters. Sensor of parallel plate capacitor is filled up with cooking oil in various concentrations, and the output voltage of the circuit is measured by using oscilloscope and also voltmeter as well. The resulted voltage values are then applied to the equation to get dielectric constant values. Finally the plot is made for dielectric constant values along the changing of cooking oil concentration. -
Part 2 - Condenser Testers and Testing Correctly Part1 Condenser Testers and Testing Correctly.Doc Rev
Part 2 - Condenser Testers and Testing Correctly Part1_Condenser_Testers_And_Testing_Correctly.doc Rev. 2.0 W. Mohat 16/04/2020 By: Bill Mohat / AOMCI Western Reserve Chapter If you have read Part 1 of this Technical Series on Condensers, you will know that the overwhelming majority of your condenser failures are due to breakdown of the insulating plastic film insulating layers inside the condenser. This allows the high voltages created by the “arcing” across your breaker points to jump through holes in the insulating film, causing your ignition system to short out. These failures, unfortunately, only happen at high voltages (often 200 to 500Volts AC)….which means that the majority of “capacitor testers" and "capacitor test techniques" will NOT find this failure mode, which is the MAJORITY of the condenser failure you are likely to encounter. Bottom line is, to test a condenser COMPLETELY, you must test it in three stages: 1) Check with a ohmmeter, or a capacitance meter, to see if the condenser is shorted or not. 2) Assuming your condenser is not shorted, use a capacitance meter to make sure it has the expected VALUE of capacitance that your motor needs. 3) Assuming you pass these first two step2, you then need to test your condenser on piece of test equipment that SPECIFICALLY tests for insulation breakdown under high voltages. (As mentioned earlier, you ohmmeter and capacitance meter only put about one volt across a capacitor when testing it. You need to put perhaps 300 or 400 times that amount of voltage across the condenser, to see if it’s insulation has failed, allowing electricity to “arc across" between the metal plates when under high voltage stress. -
Capacitance and Dissipation Factor Measurementst from 1 Khz to 10 Mhz " Presenter: A
Capacitance and Dissipation Factor Measurementst from 1 kHz to 10 MHz " Presenter: A. D. Koffman NIST, 220/B162, Gaithersburg, MD 20899 (301) 975-4518 Paper Authors A. D. Koffman, B. C. Waltrip, N. M. Oldham National Institute of Standards and TechnologY: Gaithersburg, MD S. Avramov-Zamurovic U.S. Naval Academy Annapolis, MD Abstract: A measurement technique developed by K. Yokoi et al. at Hewlett-Packard Japan, Ltd. has been duplicated and evaluated at the National Institute of Standards and Technology (NIST) to characterize four-tenninal pair capacitors. The technique is based on an accurate three-terminal measurement made at 1 kHz using a capacitance bridge and wideband single-port measurementsmadebetween30MHzand200 MHz usinga networkanalyzer. The measurement data are fitted to the four-tenninal pair admittance model defmed by R. Cutkosky to compute capacitance and dissipation factor at any frequency up to 10 MHz. Capacitors characterized using this technique will be used as impedance reference standards for a general- purpose digital impedance bridge recently developed at NIST to calibrate inductors and ac resistors. The technique could also lead to a future NIST Special Test for dissipation factor. INTRODUCTION Recent efforts by the Electricity Division at the National Institute of Standards and Technology (NIST) to develop improved impedance comparison methods from 20 Hz to 1 MHz (1)have made it necessary to fmd a means to evaluate the reference impedances used in such comparisons. The impedance-characterization method discussed in this paper is described by Suzuki, et al. (2)and is based on the four-tenninal pair impedance work of Cutkosky (3)and Jones (4,5) The four-terminal pair impedance, Z4tp'of a device is defined as a combination of its real component, R, and its imaginary component, X: Z41p= R+ jX. -
EE 462G Laboratory #1 Measuring Capacitance
EE 462G Laboratory #1 Measuring Capacitance Drs. A.V. Radun and K.D. Donohue (1/24/07) Revised by Samaneh Esfandiarpour and Dr. David Chen (9/17/2019) Department of Electrical and Computer Engineering University of Kentucky Lexington, KY 40506 I. Instructional Objectives Introduce lab instrumentation with linear circuit elements Introduce lab report format Develop and analyze measurement procedures based on two theoretical models Introduce automated lab measurement and data analysis II. Background A circuit design requires a capacitor. The value of an available capacitor cannot be determined from its markings, so the value must be measured; however a capacitance meter is not available. The only available resources are different valued resistors, a variable frequency signal generator, a digital multi-meter (DMM), and an oscilloscope. Two possible ways of measuring the capacitor’s value are described in the following paragraphs. For this experiment, the student needs to select resistors and frequencies that are convenient and feasible for the required measurements and instrumentation. Be sure to use the digital multi-meter (DMM) to measure and record the actual resistance values used in each measurement procedure. III. Pre-Laboratory Exercise Step Response Model 1. For a series circuit consisting of a voltage source v(t), resistor R, and capacitor C, derive (show all steps) the complete solution for the capacitor voltage vc(t) when the source is a step with amplitude A and the initial capacitor voltage is 0. 2. Assume the source v(t) is a function generator, where the source voltage can only be measured after the 50 Ω internal resistance. -
(ECE, NDSU) Lab 11 – Experiment Multi-Stage RC Low Pass Filters
ECE-311 (ECE, NDSU) Lab 11 – Experiment Multi-stage RC low pass filters 1. Objective In this lab you will use the single-stage RC circuit filter to build a 3-stage RC low pass filter. The objective of this lab is to show that: As more stages are added, the filter becomes able to better reject high frequency noise When plotted on a Bode plot, the gain approaches two asymptotes: the low frequency gain approaches a constant gain of 0dB while the high-frequency gain drops as 20N dB/decade where N is the number of stages. 2. Background The single stage RC filter is a low pass filter: low frequencies are passed (have a gain of one), while high frequencies are rejected (the gain goes to zero). This is a useful filter to remove noise from a signal. Many types of signals are predominantly low-frequency in nature - meaning they change slowly. This includes measurements of temperature, pressure, volume, position, speed, etc. Noise, however, tends to be at all frequencies, and is seen as the “fuzzy” line on you oscilloscope when you amplify the signal. The trick when designing a low-pass filter is to select the RC time constant so that the gain is one over the frequency range of your signal (so it is passed unchanged) but zero outside this range (to reject the noise). 3. Theoretical response One problem with adding stages to an RC filter is that each new stage loads the previous stage. This loading consumes or “bleeds” some current from the previous stage capacitor, changing the behavior of the previous stage circuit. -
Capacitance Meter MUDIT AGARWAL
Capacitance Meter MUDIT AGARWAL Nasiha Ali The principle of operating is counting the pulse oscillator during a fixed time interval produced by another lower frequency oscillator. This oscillator uses the capacitor being measured as the timing element. The capacitance measurement is proportional during pulse counting during a fixed time interval. The astable oscillator formed by IC1c K K K K K K K K K K K K K K K K K K K K K 1 1 1 1 1 1 1 9V 1 1 1 1 1 1 1 1 1 1 1 1 1 1 + + 9V produces a pulse train of constant frequency. Gate 13 12 11 10 9 15 14 3 3 13 12 11 10 9 15 14 13 12 11 10 9 15 14 3 IC4 IC5 IC6 4 4 8 8 4 IC1a also form oscillator whose oscillation period 4511 4511 8 4511 16 5 6 2 1 7 16 16 5 6 2 1 7 6 2 1 7 5 is given approximately by the equation: T=0.7RC. 1C1c Period T is linearly dependent on the capacitance 4093 9 6 5 4 3 2 14131211 10 8 6 5 4 3 16 2 IC2 IC3 10 1 1 C. This period is used as the time interval for one 4518 4518 8 9 7 15 7 15 9 1.5M measurement. The differentiator network following 2K C1 the oscillator creates the negative spikes shaped in 1C1a 9V + 220pf 4093 14 K 1 5 1 9 3 4 R K narrow pulses by IC1b NAND Schmitt trigger. -
Time Constant Calculations This Worksheet and All Related Files Are
Time constant calculations This worksheet and all related files are licensed under the Creative Commons Attribution License, version 1.0. To view a copy of this license, visit http://creativecommons.org/licenses/by/1.0/, or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA. The terms and conditions of this license allow for free copying, distribution, and/or modification of all licensed works by the general public. Resources and methods for learning about these subjects (list a few here, in preparation for your research): 1 Questions Question 1 Qualitatively determine the voltages across all components as well as the current through all components in this simple RC circuit at three different times: (1) just before the switch closes, (2) at the instant the switch contacts touch, and (3) after the switch has been closed for a long time. Assume that the capacitor begins in a completely discharged state: Before the At the instant of Long after the switch switch closes: switch closure: has closed: C C C R R R Express your answers qualitatively: ”maximum,” ”minimum,” or perhaps ”zero” if you know that to be the case. Before the switch closes: VC = VR = Vswitch = I = At the instant of switch closure: VC = VR = Vswitch = I = Long after the switch has closed: VC = VR = Vswitch = I = Hint: a graph may be a helpful tool for determining the answers! file 01811 2 Question 2 Qualitatively determine the voltages across all components as well as the current through all components in this simple LR circuit at three different times: (1) just before the switch closes, (2) at the instant the switch contacts touch, and (3) after the switch has been closed for a long time. -
LCR Meter PCE-UT 603
www.pce-industrial-needs.com Tursdale Technical Services Ltd Unit N12B Tursdale Business Park Co. Durham DH6 5PG United Kingdom Phone: +44 ( 0 ) 191 377 3398 Fax: +44 ( 0 ) 191 377 3357 [email protected] http://www.industrial-needs.com/ Manual LCR Meter PCE-UT 603 [email protected] Table of contents Overview .................................................................................................................................................. 3 Safety Information ................................................................................................................................... 3 Rules for Safe Operation .......................................................................................................................... 3 International Electrical Symbols .............................................................................................................. 4 The Meter Structure ................................................................................................................................. 4 Functional Buttons ................................................................................................................................... 5 Display Symbols ...................................................................................................................................... 5 Measurement Operation ........................................................................................................................... 6 A. Measuring -
Cutoff Frequency, Lightning, RC Time Constant, Schumann Resonance, Spherical Capacitance
International Journal of Theoretical and Mathematical Physics 2019, 9(5): 121-130 DOI: 10.5923/j.ijtmp.20190905.01 Solar System Electrostatic Motor Theory Greg Poole Industrial Tests, Inc., Rocklin, CA, United States Abstract In this paper, the solar system has been visualized as an electrostatic motor for the research of scientific concepts. The Earth and space have all been represented as spherical capacitors to derive time constants from simple RC theory. Using known wave impedance values (R) from antenna theory and celestial capacitance (C) several time constants are derived which collectively represent time itself. Equations from Electro Relativity are verified using known values and constants to confirm wave impedance values are applicable to the earth antenna. Dark energy can be represented as a tremendous capacitor voltage and dark matter as characteristic transmission line impedance. Cosmic energy transfer may be limited to the known wave impedance of 377 Ω. Harvesting of energy wirelessly at the Earth’s surface or from the Sun in space may be feasible by matching the power supply source impedance to a load impedance. Separating the various the three fields allows us to see how high-altitude lightning is produced and the earth maintains its atmospheric voltage. Spacetime, is space and time, defined by the radial size and discharge time of a spherical or toroid capacitor. Keywords Cutoff Frequency, Lightning, RC Time Constant, Schumann Resonance, Spherical Capacitance the nearest thimble, and so put the wheel in motion; that 1. Introduction thimble, in passing by, receives a spark, and thereby being electrified is repelled and so driven forwards; while a second In 1749, Benjamin Franklin first invented the electrical being attracted, approaches the wire, receives a spark, and jack or electrostatic wheel. -
The RC Circuit
The RC Circuit The RC Circuit Pre-lab questions 1. What is the meaning of the time constant, RC? 2. Show that RC has units of time. 3. Why isn’t the time constant defined to be the time it takes the capacitor to become fully charged or discharged? 4. Explain conceptually why the time constant is larger for increased resistance. 5. What does an oscilloscope measure? 6. Why can’t we use a multimeter to measure the voltage in the second half of this lab? 7. Draw and label a graph that shows the voltage across a capacitor that is charging and discharging (as in this experiment). 8. Set up a data table for part one. (V, t (0-300s in 20s intervals, 360, and 420s)) Introduction The goal in this lab is to observe the time-varying voltages in several simple circuits involving a capacitor and resistor. In the first part, you will use very simple tools to measure the voltage as a function of time: a multimeter and a stopwatch. Your lab write-up will deal primarily with data taken in this part. In the second part of the lab, you will use an oscilloscope, a much more sophisticated and powerful laboratory instrument, to observe time behavior of an RC circuit on a much faster timescale. Your observations in this part will be mostly qualitative, although you will be asked to make several rough measurements using the oscilloscope. Part 1. Capacitor Discharging Through a Resistor You will measure the voltage across a capacitor as a function of time as the capacitor discharges through a resistor. -
Voltage Divider Capacitor RC Circuits
Physics 120/220 Voltage Divider Capacitor RC circuits Prof. Anyes Taffard Voltage Divider 2 The figure is called a voltage divider. It’s one of the most useful and important circuit elements we will encounter. It is used to generate a particular voltage for a large fixed Vin. Vin Current (R1 & R2) I = R1 + R2 Output voltage: R 2 Voltage drop is Vout = IR2 = Vin ∴Vout ≤ Vin R1 + R2 proportional to the resistances Vout can be used to drive a circuit that needs a voltage lower than Vin. Voltage Divider (cont.) 3 Add load resistor RL in parallel to R2. You can model R2 and RL as one resistor (parallel combination), then calculate Vout for this new voltage divider R2 If RL >> R2, then the output voltage is still: VL = Vin R1 + R2 However, if RL is comparable to R2, VL is reduced. We say that the circuit is “loaded”. Ideal voltage and current sources 4 Voltage source: provides fixed Vout regardless of current/load resistance. Has zero internal resistance (perfect battery). Real voltage source supplies only finite max I. Current source: provides fixed Iout regardless of voltage/load resistance. Has infinite resistance. Real current source have limit on voltage they can provide. Voltage source • More common • In almost every circuit • Battery or Power Supply (PS) Thevenin’s theorem 5 Thevenin’s theorem states that any two terminals network of R & V sources has an equivalent circuit consisting of a single voltage source VTH and a single resistor RTH. To find the Thevenin’s equivalent VTH & RTH: V V • For an “open circuit” (RLà∞), then Th = open circuit • Voltage drops across device when disconnected from circuit – no external load attached.