Free electronic circuit design and schematic diagram
This is a 1.5 to 9 volts inverter schematic circuit. This is low cost and a simple circuit that need few components.This circuit is used in many application that requires 9 volts power supply. using this circuit we can replace the expensive 9v batteries. This circuit can convert 1.5V to 9V. This circuit can be used only for application that […]
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It is still possible to build circuits without IC’s and still achieve a high level of performance while integrated circuits have become a staple of all modern circuit designs. A high performance 5 volt voltage regulator built using discrete components that are readily available is shown on circuit diagram below. This circuit not need an IC and only need to […]
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This is simple 2N3055 Variable power supply circuit. This circuit has some advantages such as it it can deliver an output voltage between 1,5 V and 15 V with a 500 mA maximum current and low production cost. If the current consumption do not exceed 350 mA, the circuit has stabilization of better than 2%. Here is the circuit: The […]
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This is a simple 220V power interface circuit. This circuit used as interface for monitoring electric devices and equipments using a computer. The circuit only senses whether the device being monitored is turned off or on. The galvanic isolation between the AC main line being monitored and the interface to the computer is an important aspect of the circuit. We […]
Read moreThere are several integrated circuit chips designed specially for LDO (low drop out) voltage regulator. Building LDO using standard op-amp and discrete components can be an alternative. Here is one design of LDO circuit: Here some guidelines to select the components values: D1 is chosen for the best performance, the sharper the on-off transition curve the better. Some people say […]
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Ni Cad batteries can be charged at high current rates because it allows short charge time. But, it has difficulty in operations such as excessive internal heating degrades the batteries and can cause gas venting to the outside atmosphere. Because cell voltage is not necessarily indicative of the charge state of the battery , schemes based on monitoring cell voltage […]
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This is a Auto-Off Power Source circuit. This circuit is used to turn off the power source automatically. This circuit uses the MAX931 that has key features such as high current output, an internal reference, 2.5µA supply current, and hysteresis. This circuit requires only 3.5uA quiescent current to provide voltage of Vbatt -0.12V with 10mA load. Here is the circuit: […]
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