02-10-2010, 04:48 PM
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This article is presented by:
NARESH . V
BHASKAR. L
MYOELECTRIC CONTROLLED PROSTHETIC HAND
ABSTRACT
Our mini project was inductance meter using 89c2051 microcontroller. As an expansion and knowledge improvement we have opted for LCF meter as our final year project. Which is not only challenging but also useful device. To be different our choice was LCF meter (inductance , capacitance and frequency meter), instead of LCR meter
INTRODUCTION
Capacitance meter:
Capacitance meter can be very helpful in identifying old components where its mark has been erased or became unreadable. Such instrument can be quite expensive, but fortunately we can build it easily with much lower cost. The capacitance meter described here can measure any capacitor between 1pF and 10uF. Here is the schematic diagram of the circuit:You can just use a connector for the voltmeter, and the circuit becomes a capacitance meter adapter for your general purpose voltmeter. Just plug the input of your voltmeter to this capacitance meter circuit and now your voltmeter becomes capacitance meter.
You can use an analog voltmeter or digital voltmeter. If you use a digital voltmeter, make sure your digital voltmeter is a dual/single slope type reading, since it has an inherent averaging function. If your digital voltmeter is a fast sampling type, then you need to insert a resitor-capacitor filter between this capacitance meter circuit and the voltmeter. A 1k resitor and a 10uF electrolytic capacitor sould be enough for the filter. Analog voltmeter doesn’t need any filter since its mechanical inertia acts like a low-pass filter in nature. More information can be found at
This simple controller based unit was designed to measure and display the values of inductors and capacitors.As a by-product of the technique used.it can also display the frequency of an external 0V/ +5V signal source The ranges are approximately:
Capacitance : 1pF to 6500uF
Inductance : 1uH to 10H
Frequency : 0.05Hz to 5MHz
Inductance meter:
The algorithm works with the device is as follows:
1. After the power, if the buttons SA1, SA2 are pressed, then the indicator will show "L" or "C", thus hinting at what button must be overcome.
2. When squeezed the knob, the instrument calibration mode, as evidenced by the inscription "WAIT", a couple of seconds, alternating on "OK". During this time, the relay, including a reference capacitor in the general contour of the L1 and C1. The microcontroller reads the frequency with condenser and without him, which then e yshem will be used to calculate the exact values of L1 and C1. Measuring terminals at this time disconnected from the circuit and do not affect the measurement.
3. By clicking on the appropriate radio button is selected or the measurement of capacitance or inductance. Accordingly, the indicator displays "L =", or "C =". In the first case, the measured capacitance connected in parallel with C1, the second - as measured inductance connected in series L1. Microcontroller measures the frequency and computes the desired value. The limit of measurement is set automatically, and after the indicated values of the dimension: "pF", "nF", " uH "," mH ".
Frequency counter:
Digital frequency counter is being used for wide range of applications. Digital frequency counter is extensively uses digital circuits and hence fairly good knowledge of digital circuits and of digital integrated circuits is required to understand the operation of the frequency counter. However application of micro controllers have greatly simplified hardware requirement for frequency counter. The following figure shows the conventional frequency counter design.
INTRODUCTION
Capacitance meter:
Capacitance meter can be very helpful in identifying old components where its mark has been erased or became unreadable. Such instrument can be quite expensive, but fortunately we can build it easily with much lower cost. The capacitance meter described here can measure any capacitor between 1pF and 10uF. Here is the schematic diagram of the circuit:You can just use a connector for the voltmeter, and the circuit becomes a capacitance meter adapter for your general purpose voltmeter. Just plug the input of your voltmeter to this capacitance meter circuit and now your voltmeter becomes capacitance meter.
You can use an analog voltmeter or digital voltmeter. If you use a digital voltmeter, make sure your digital voltmeter is a dual/single slope type reading, since it has an inherent averaging function. If your digital voltmeter is a fast sampling type, then you need to insert a resitor-capacitor filter between this capacitance meter circuit and the voltmeter. A 1k resitor and a 10uF electrolytic capacitor sould be enough for the filter. Analog voltmeter doesn’t need any filter since its mechanical inertia acts like a low-pass filter in nature. More information can be found at
This simple controller based unit was designed to measure and display the values of inductors and capacitors.As a by-product of the technique used.it can also display the frequency of an external 0V/ +5V signal source The ranges are approximately:
Capacitance : 1pF to 6500uF
Inductance : 1uH to 10H
Frequency : 0.05Hz to 5MHz
Inductance meter:
The algorithm works with the device is as follows:
1. After the power, if the buttons SA1, SA2 are pressed, then the indicator will show "L" or "C", thus hinting at what button must be overcome.
2. When squeezed the knob, the instrument calibration mode, as evidenced by the inscription "WAIT", a couple of seconds, alternating on "OK". During this time, the relay, including a reference capacitor in the general contour of the L1 and C1. The microcontroller reads the frequency with condenser and without him, which then e yshem will be used to calculate the exact values of L1 and C1. Measuring terminals at this time disconnected from the circuit and do not affect the measurement.
3. By clicking on the appropriate radio button is selected or the measurement of capacitance or inductance. Accordingly, the indicator displays "L =", or "C =". In the first case, the measured capacitance connected in parallel with C1, the second - as measured inductance connected in series L1. Microcontroller measures the frequency and computes the desired value. The limit of measurement is set automatically, and after the indicated values of the dimension: "pF", "nF", " uH "," mH ".
Frequency counter:
Digital frequency counter is being used for wide range of applications. Digital frequency counter is extensively uses digital circuits and hence fairly good knowledge of digital circuits and of digital integrated circuits is required to understand the operation of the frequency counter. However application of micro controllers have greatly simplified hardware requirement for frequency counter. The following figure shows the conventional frequency counter design.
