Free electronic circuit design and schematic diagram
Metal Detector Circuit Topology One of the simplest method of metal detecting is by beat frequency oscillator. Basically, the circuit consist of two balanced oscillator. One oscillator provides the reference signal, and other oscillator is acting as the detector element. The reference oscillator’s frequency is fix, while the detector oscillator is variable depending on the presence of a metal. The […]
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This radio modem is popular for amateur radio packet application. This radio modem is powered by the data and control lines, so it need no additional power supply. Just plug to your standard RS232 port and this modem will work. As seen in our previous modem circuit, this radio modem circuit also uses TCM3105 modem chip from Texas Instruments. To […]
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This circuit uses MM74HC942, a single chip low-speed modem which is compatible with Bell 103 standard. This Bell 103 modem circuit is run at 300 baud in full duplex (bidirectional). The frequency and sine wave synthesizer inside this modem chip generate phase-coherent FSK modulation for the best bit accuracy. Here is the schematic diagram of the modem circuit: This single […]
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Imagine you have a master controller device that control other devices in your house, and you don’t need to install any additional wires to facilitate the data communication between the master controller and the controlled devices. Yes you’s life will be easier since all you need is just plugging your devices into your power line outlet, the devices will communicate […]
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Using TCM3105 FSK modem chip from Texas Instruments, you can easily build a Bell 202 or CCITT V23 compatible modem. This modem circuit is capable transmitting the data at 75, 150, 600, and 1200 baud, and receive the data at 5, 75, 150, 600, and 1200 baud. This circuit operate at 5V supply and has low power consumption feature. Here […]
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For battery operated devices, this class D amplifier is suitable because its high efficiency (85%) helps extend the battery life. In the internal circuitry, a boost converter with over 90% efficiency is provided to step-up the voltage supply, and need only one external inductor as the additional component for this function. When driving 8 ohm loud speaker, this class-D amplifier […]
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This class-D audio power amplifier is suitable for TV and home stereo set. TDA7882 IC chip provides class-D audio power amplifier solution. Since this chip has only mono channel, you need two pieces of this circuit for stereo application. The power supply voltage is flexible, accept (+-)10V to (+-)25V. This circuit needs a split supply (symmetric power supply). Here are […]
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