Free electronic circuit design and schematic diagram
In automotive environment, it’s common that only single voltage power outlet is available. Using the very popular LM317 voltage regulator IC, we can build a general purpose DC adapter to adapt car’s power outlet voltage (12-14 Volts) to supply small DC devices requiring lower voltage level. On the following schematic diagram for the car power adapter, we can see that […]
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We can build a multiple voltage power supply 6, 9, and 12V (AC-DC Adapter) with the circuit shown in the following schematic diagram. Not only provide multiple voltage output with single voltage supply, this circuit add the benefit of regulating the voltage for better stability. The TIP31 transistor should be installed with proper heat-sink to prevent overheating. A transformer […]
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This transformer-rectifier-filter arrangement gives you multiple output voltages with a single transformer. This AC-DC converter can be your solution is you need two level of symmetric power supply. Here is the schematic diagram of the circuit: U1 and -U1 uses a basic symmetric supply configuration, with a center-tapped transformer and full bridge rectifier for. U2 and -U2 uses a voltage […]
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This is a protocol translator circuit. This circuit uses the MAX3162, it contains both RS-485 and RS-232 transmitters and receivers. This IC contains wide range of communication devices, that can convert bidirectionally between RS-485 and RS-232 signals. Here is the circuit : The upper circuit is the translator for point to point application, and the lower is for multipoint application. […]
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In the simplest form, current to voltage converter can be implemented as simple as one resistor, since a voltage is developed when an electrical current flow against a resistance. The problem is that the resistance always affect the current by decreasing the current flow, and the current to voltage conversion is not accurate. In some cases, the resistor that convert […]
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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 external components. Here is the […]
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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 is connected to TxD, and […]
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