Free electronic circuit design and schematic diagram
For critical operation, the power loss can be unacceptable. It might be costly if a financial data is lost from the memory in the middle of point of sale transaction, or even it can be deadly if some life support devices fails during critical surgery. The schematic diagram presented here is a battery backup regulator circuit, useful for memory or […]
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An overvoltage protector circuit is shown in the schematic diagram below. This circuit will work to disconnect the protected device from the power supply when an overvoltage occurs at the supply. This circuit uses a silicon-controlled rectifier (SCR) and normally-closed 12-V relay, K1. The silicon-controlled rectifier is connected in parallel to 12-V line to monitor for the overvoltage condition. This […]
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This is a transceiver saver circuit that protect a transceiver device (applicable to other device as well) from overvoltage of the power supply. This circuit is used to protect the device by regulating the power supply, avoiding damaging the device if overvoltage occurs. If the transceiver transmits current of above 2A, a heatsink should be used for the transistor. 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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We can use a circuit breakers to limit the current in a single circuit in most household applications. Although breakers come in many sizes, typically a single circuit is limited to 20 amperes. This means that to bend it downward and release the spring-loaded trip-lever, 20 amps of current will heat the bimetallic strip. Another mechanism is employed to handle […]
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This is a Overvoltage Protected 5V Power Supply circuit. This circuit can be used to supply 74LS series integrated circuit and TTL. This circuit can protect the TTL or 74Ls series integrated circuit from damage because these ICs are easily damaged by short voltage spikes. This circuit uses a fuse which if the current rating is exceeded, the fuse will […]
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When you insert peripherals, a problem can occur : The sudden load on the port’s 5V pin usually isn’t purely resistive. This load has a capacitive component that can cause a rapid and high-amplitude rise in current to levels well above the 500mA limit for USB port. When you connect a too-large hard disk to the port, a similar problem […]
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