Universal Counter Timer: All measurements of time period and frequency by various circuits can be assembled together to form one complete block, called a Universal Counter Timer. The universal counter uses logic gates which are selected and controlled by a single front panel switch, known as the function switch. A simplified block diagram is shown […]
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Digital Measurement of Time: Principle of Operation of Digital Measurement of Time – The beginning of the time period is the start pulse originating from input 1, and the end of the time period is the stop pulse coming from input 2. The oscillator runs continuously, but the oscillator pulses reach the output only during
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Digital Frequency Meter: Principle of Operation of Digital Frequency Meter – The signal waveform is converted to trigger pulses and applied continuously to an AND gate, as shown in Fig. 6.4. A pulse of 1 s is applied to the other terminal, and the number of pulses counted during this period indicates the frequency. The
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Working Principle of Digital Multimeter: Analog meters require no power supply, they give a better visual indication of changes and suffer less from electric noise and isolation problems. These meters are simple and inexpensive. Digital meters, on the other hand, offer high accuracy, have a high input impedance and are smaller in size. They gives
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What is a Digital Instrument?: Digital instrument are rapidly replacing their analog counterparts. The parameters of interest in a laboratory environment are (i) voltage (ii) current (iii) power (iv) frequency, and (v) logic. We shall consider digital systems which measure the above parameters. To enable digital systems to recognize information, inputs which are analog in
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Microprocessor Based Ramp Type DVM: A basic block diagram of a Microprocessor Based Ramp Type DVM and its operating waveform is shown in Fig. 5.17 (a) and (b) respectively. Depending on the command fed to the control input of the multiplexer by the microprocessor, input 1 of the comparator can be consecutively connected to the
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Continuous Balance DVM: Continuous Balance DVM – The basic block diagram of a servo balancing potentiometer type DVM is shown in Fig. 5.15. The input voltage is applied to one side of a mechanical chopper comparator, the other side being connected to the variable arm of a precision potentiometer. The output of the chopper comparator,
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Successive Approximation Type DVM: The Successive Approximation Type DVM principle can be easily understood using a simple example; the determination of the weight of an object. By using a balance and placing the object on one side and an approximate weight on the other side, the weight of the object is determined. If the weight
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Principles of ADC (Analog to Digital Conversion): Principles of ADC – The input signal is compared with an internally generated voltage which is increased in steps starting from zero. The number of steps needed to reach the full compensation is counted. A simple compensation type is the staircase ramp. Block diagram of Staircase Ramp Type:
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Integrating Type DVM (Voltage to Frequency Conversion): The principle of operation of an Integrating Type DVM is illustrated in Fig. 5.5. A constant input voltage is integrated and the slope of the output ramp is proportional to the input voltage. When the output reaches a certain value, it is discharged to 0 and another cycle
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