This website uses cookies to ensure you have the best experience. Learn more

Comparator Essay

1059 words - 5 pages

Capacitive Reactance
In the RC Network tutorial we saw that when a DC voltage is applied to a capacitor, the capacitor itself draws a charging current from the supply and charges up to a value equal to the applied voltage. Likewise, when the supply voltage is reduced the charge stored in the capacitor also reduces and the capacitor discharges.
In an AC circuit in which the applied voltage signal is continually changing from a positive to a negative polarity at a rate determined by the frequency of the supply, as in the case of a sine wave voltage, for example. The capacitor is either being charged or discharged on a continuous basis at a rate determined by the frequency. As the capacitor ...view middle of the document...

Capacitive Reactance has the electrical symbol "Xc" and has units measured in Ohms the same as resistance, ( R ). It is calculated using the following formula:
Capacitive Reactance

Capacitive Reactance Formula

• Where:
• Xc = Capacitive Reactance in Ohms, (Ω)
• π (pi) = 3.142 or 22/7
• ƒ = Frequency in Hertz, (Hz)
• C = Capacitance in Farads, (F)
Example No1
Calculate the capacitive reactance of a 220nF capacitor at a frequency of 1kHz and again at 20kHz.
At a frequency of 1kHz,

Again at a frequency of 20kHz,

where: ƒ = frequency in Hertz and C = capacitance in Farads
It can be seen that as the frequency applied to our 220nF capacitor increases from 1kHz to 20kHz, its reactance decreases from approx 723Ωs to just 36Ωs. For any given value of capacitance the reactance of a capacitor can be plotted against the frequency as shown below.
Capacitive Reactance against Frequency

By re-arranging the reactance formula above, we can also find at what frequency a capacitor will have a particular capacitive reactance ( XC ) value.
Example No1 - At which frequency would a 2.2uF Capacitor have a reactance value of 200Ωs?

Or we can find the value of the capacitor in Farads by knowing the applied frequency and its reactance value at that frequency.
Example No2 - What will be the value of a Capacitor in farads when it has a capacitive reactance of 200Ω and is connected to a 50Hz supply.

We can see from the above examples that a capacitor when connected to a variable frequency supply, acts a bit like a "frequency controlled variable resistor". At very low frequencies, such as 1Hz our 220nF capacitor has a high capacitive reactance value of approx 723KΩs (giving the effect of an open circuit). At very high frequencies such as 1Mhz the capacitor has a low capacitive reactance value of just 0.7 ohms (giving the effect of a short circuit). At zero frequency or steady state DC the capacitor has infinite reactance looking more like an "open-circuit" between the plates and blocking any flow of current through it.
Voltage Divider Revision
We remember from our tutorial about Resistors in Series that different voltages...

Other Papers Like Comparator

Artificial Inteligence In The World Today

3097 words - 13 pages sensor and a comparator. The sensor reads raw data from the environment and the comparator uses this data to adjust the output of the circuit to correct any problems. The data in traditional logic is either is either true or false when it reaches the comparator. This means that the output is either on or off. An example will be a circuit used to control a cooling fan with a requirement that the fan needs to come on at 90 degrees to cool the room

Compensation Essay

1295 words - 6 pages . Under pay equity legislation, organizations are required to use these 4 categories in evaluating work. They also typically include – job inputs, outputs, requirements and conditions. What are benchmarking jobs? What are they used for? (283) It is a job in the firm’s job evaluation system for which there is a good match in the labour market data. These jobs are picked because of the available data of the market comparator job. From these

Uk Post Office

7765 words - 32 pages public bodies have relied on in evaluating up-front whether a Private Finance Initiative option provides better value for money over conventional procurement is a public sector comparator. A public sector comparator is a costing of a conventionally OECD JOURNAL ON BUDGETING – VOLUME 5 – NO. 3 – ISSN 1608-7143 © OECD 2006 THE UNITED KINGDOM PRIVATE FINANCE INITIATIVE: THE CHALLENGE OF ALLOCATING RISK – 43 financed project delivering the


4408 words - 18 pages Features • Compatible with MCS®-51Products • 2K Bytes of Reprogrammable Flash Memory • • • • • • • • • • • • – Endurance: 10,000 Write/Erase Cycles 2.7V to 6V Operating Range Fully Static Operation: 0 Hz to 24 MHz Two-level Program Memory Lock 128 x 8-bit Internal RAM 15 Programmable I/O Lines Two 16-bit Timer/Counters Six Interrupt Sources Programmable Serial UART Channel Direct LED Drive Outputs On-chip Analog Comparator Low-power Idle and

Employment Law

1626 words - 7 pages to identify a comparator. In bringing a discrimination claim, Elodie’s claim is bolstered as she would use Sam as a comparator, and the burden would be on the Nursery to prove that their decision to dismiss was not on the grounds of race.

Hrm Pay, Appraisal, Discipline, Grievance And Personnel Records Case Study

3913 words - 16 pages Human Resource Management Assignment 3 Report to Board of Directors Subject: Pay, Appraisal, Discipline, Grievance and Personnel records Job Descriptions and Pay Findings | |Softworks |Barnsley MBC (Comparator) | |Job Description |No Formal job descriptions |Formal

Computer Science Notes

5011 words - 21 pages in changing environment Maintenance matters and cost even if released code has zero defects To make your code maintainable Interfaces Interface: its set of methods that supports the API Back to java: comparable/comparator In computing, we often want to order a set of items Find the max, best or min, worst Sort them in order Need a way to compare using different criteria Wanta flexable way to compare using different criteria Let us use


1913 words - 8 pages observed for algal growth. As a metric for the amount of growth, an “Algal Growth Comparator” (fig 3) was used. Observable growth was recorded by four different individuals for each tube and the results were averaged for use in statistical data set used to develop the graphs to follow in the results section fig. 3 Algal growth comparator These experiments were the

Power Factor Correction Using Boost Converter

4108 words - 17 pages ) Customers where also surveyed to assess what other motor loads, such as pumps, power tools, extra refrigerators, pools or hot tubs may be within their homes. A complete inventory list can be found in Appendix D. These averages where applied to the customers fed from the baseline transformer. This gave us a comparator as to the number of appliances and family members were in each home. Upon completion of the pilot a follow up phone survey was

Buying or Renting: Which Is Better for You?

1625 words - 7 pages . One might choose to use a buy vs rent comparison tool such as the mortgage calculator that can be provided by a lender or real estate broker. The Rent versus Buy Comparator allows the user to compare their estimated financial position after 7 years of renting with their estimated financial position after 7 years of home loan repayments (, n.d.). This tool will allow the buyer or renter to compare the possible financial cost and

Ppp and Project Financing in Logistics Infrastructure

2337 words - 10 pages in Infrastructure”, Review of Industrial Organization, n. 26, 2006. Esty, B.C. Why Study Large Projects? An Introduction to Research on Project Finance European Financial Management, Vol. 10, No. 2, 2004. Esty, B.C., “Modern project Finance: A Casebook” Wiley, New York 2004. HM Treasury, Value for Money Assessment Guidance, London, 2006 HM Treasury, Technical note N. 5, How to construct a Public Sector Comparator, London 2007 Nevitt, P.K

Related Essays

Pulse Width Modulation Essay

530 words - 3 pages , square and triangle wave. QUESTION 1. What are the functions of VR1? VR1 is a variable resistor used to adjust the input terminal Vin(+) operation voltage. When we adjust VR1, then the Vin(+) input terminal operation voltage will change, which means the reference voltage comparator will change, thus the output signal of pulse width will also change too. If the VR1 is fixed, it means that the operation voltage of Vin(+) input terminal is

Race Equality Essay

3083 words - 13 pages clear that a comparator is necessary so if there is no actual comparator available then a hypothetical comparator should be used instead. This aspect of discrimination is not so much incorporated in the Crime and Disorder Act in relation to racially aggravated offences and there is no such requirement for the victim to have been less favourably treated compared to someone who is not of the same race. For example under the concept of direct

Eye Blink Sensor Essay

3045 words - 13 pages …………………………...………..………..9 2.3.1 IR Sensing Circuit………..…….………..……………….9 2.3.2 Alarm Circuit……..………………………………………11 2.3.3 LM358 Comparator………….………………………….13 3. Hardware Description………………………………………..……….. 14 3.1 Microcontroller (AT89S52)……………………………..………..16 3.2 Liquid Crystal Display….……..……………………………….. 18 3.3 Power Supply….………………….………………….………….20 4. Software……………………………………………………….………..22

Architecture For Statistical Multiplexer Essay

1801 words - 8 pages in the system computes the convolution of all PDF of source data rate, which is already stored in the memory. Its output is fed to the probability computation unit. Probability computation unit compute the probability of combining data rate Y is greater than the maximum data rate of the output, i.e. P(Y>L)=∫_L^∞▒〖f_Y (y) □(24&dy)〗 Flow Chart The comparator unit compares the output of probability computation unit with a threshold value which is