Archive for the ‘Data Communication’ Category
Constant Current Constant Voltage SMPS (Switch Mode Power Supply)
This constant current constant voltage SMPS can be used to efficiently charge a battery. This circuit gives 7.2V at constant voltage mode, and 600 mA at constant current mode. Here is the schematic diagram of the circuit: The mechanism is simple, when the load impedance is high, then the output voltage will be constant at …[Read More]
Integrator Circuit With Reset
Integration is one of basic signal processing that can be done in analog domain. Using operational amplifier (op-amp), integration operation can be done with very simple circuit with very high accuracy. Here is the schematic diagram of an integrator circuit: The resistor R2 should have the same value with R1 since R2 is employed to …[Read More]
Using MAX232 integrated circuit, you can build a TTL-to-RS232 level converter that totally comply with RS232 electrical specification. The IC generate the higher positive and negative voltage (+10 and -10 Volts) from TTL power supply (5V DC) using switched capacitor. The switching circuitry is provided inside the chip, so you need only few caps for …[Read More]
Simple TTL-RS232 Level Converter Using Transistor
Using only transistors as the active components, we can build a simple and low cost TTL-to-RS232 level converter. It uses only two transistors as the active components. Here is the schematic diagram of the converter: You can use any small signal transistor for this RS232 converter circuit. You can see the collector of Q1 transistor …[Read More]
USB-RS232 Converter
Many new computers now only has USB port, and this serial to USB adapter might be the only help for old devices that provides only RS232/COM Port. This serial adapter uses FT232 USB-RS232 converter IC from FTDI (Future Technology Devices International). The main features of this USB serial adapter chip are: 384 byte receive buffer …[Read More]
RS232 to RS485 Converter
RS485 interface gives some more benefits compared to RS232: simplicity and the robustness for long distance transfer. RS485 is simpler because it uses only two wire (or a single pair) to carry out the data in bidirectional manner, using RS232, we need 3 wires at minimum to carry the data bidirectionally. RS485 cable length can …[Read More]
Radio Modem Circuit
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 …[Read More]
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