Free electronic circuit design and schematic diagram
If we want to record very low frequency or DC signal on an audio recording system, we have to convert the DC/low frequency signal into the spectrum of audible sound. The figure of DC response data recording system is shown below. We can record low-frequency analog data (DC to 10kHz) anywhere, store, and then reproduced. The frequency spectrum of the […]
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It is advantageous to convert the analog signal into a digital signal, which is less susceptible to noise pick-up when transmitting analog data over long distances. It is very easy for noise to interfere the amplitude of a signal, but it would be harder to change its frequency. The TC9400 converts the input voltage into a pulse or square wave […]
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Look at the schematic diagram of a circuit below, imagine if the capacitor C1 is not charged and the power is off. There will be no current flow and Q3 will be open. The Base of Q3 will be high and the Base of Q2 low. The circuit is in stable condition and nothing happening. Power will flow through the […]
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We can say in simple words that AFC will lock the receiver to any valid RF signal. Below, we can see a basic block diagram of an receiver. The VCO is mixed with the RF signal which enter the mixer (yellow). The VCO can be a coil and a tunable capacitor. To bring out the sound from the FM signal, […]
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The TC9400 converts the analog input (Vin) ito frequencies (10Hz to 100KHz) which can be used to modulate an RF transmitter in a telemetry system. At the other end, The RF signal is picked up by receiver and it’s demodulated back into the 10Hz to 100KHz spectrum. A count linearly proportional to the original analog voltage (Vin) is given by […]
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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 […]
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Power dropout detection is often required by digital system driven from the AC line. A memory store command to be issued before DC power falls is allowed by fast AC line drop out detection. The circuit on figure below detects AC dropout by connecting an optoisolator across the power transformer’s rectified secondary. Normally, the LED is turned on by the […]
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