Free electronic circuit design and schematic diagram
Telephone line is designed to carry audio signal, which is an alternating current in nature. To transmit measurement signal, which has very low frequency or DC signal, we have to convert the signal into AC with acceptable frequency range for telephone line transmission. For transmitting analog data over telephone lines, its ideal to use the TC9400’s square-wave output. Since the […]
Read moreTurning long term integrator into bipolar input introduce a concept similar to “negative frequency”, where the counter would react to decrement its counter when a negative frequency is supplied. Off course there’s no such concept in reality, but we can achieve the same function by rectifying the input before converted to frequency, and detecting the polarity to control the up-down […]
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Measuring charge amount in electroplating, or measuring actual battery capacity can be done with integrator. Special requirement for this integrator is that it should has no leakage for long term operation, ranging for hours to several days. Using a voltage-to-frequency converter and a counter can solve this problem, here is the block diagram of the system: The counting values is […]
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The voltage that control a V/F converters will be displayed if we use a frequency counter, which is directly proportional to the input voltage. A 1 second time base will give 4 digit resolution with 1 reading per second when the V/F converters is running at 10KHz full scale. To transmit the frequency, we can use the optoisolator, so there […]
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If we don’t need a very fast analog-to-digital conversion (ADC), by combining TC9400 V/F converter with a counter, latch and time base, we can build a13 bit binary A/D converter. A 1 second time base will provide one conversion per second when the V/F converter is set up for 10KHz full scale. The high input impedance of TC9400 make it […]
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To accomplish A/D conversion with V/F converter in a microcontroller system, there are two schemes that can be utilized. First, VIN is measured by counting the FOUT frequency for 1ms, 10ms, 100ms, or 1 second depending on the number of digits of resolution required. The final count is then directly proportional to VIN. (The microcontroller provides the time base) .Second, […]
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Temperature measurement (sensing) and monitoring will be economical and straightforward if we apply the input of TC9400 V/F converter with a voltage from output of a probe, such as shown in diagram below. The V/F output is simply counted to display the temperature. The TC9400 can be used to modulate an RF transmitter for a long distance data transmission. The […]
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