Universal Alarm (Smoke alarm and then some)

Just add a few external components to a standard low-cost smoke alarm and turn it into a universal alarm sounder. You can easily hook up the outputs from any number of sensors or detectors to trigger the alarm and the smoke detector still functions as normal. Down in our cellar we have a sump pump to automatically pump out any ground water that...

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0-50V 2A Bench power supply

An 0-50v bench power supply can be made using electronic diagram below which is designed using LM10 op amp and 2n3055 transistors. 50V Bench Power Supply Circuit Diagram: This LM10 2n3055 50v bench power supply allows an output voltage regulation in a range between 0 and 50 volts and the output current can be limited to a maximum of 2A. Output...

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Transformerless 5 Volt DC Power Supply

An increasing number of appliances draw a very small current from the power supply. If you need to design a mains-powered device, you could generally choose between a linear and a switch-mode power supply. However, what if the appliance’s total power consumption is very small? Transformer-based power supplies are bulky, while the switchers are generally...

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Temperature Sensor Circuit using 1N4148 diode

There are components that have special characteristics, one of them is the 1N4148 diode, it is a diode High-speed, and its switching speed is 4th, its voltage is 100 V and current of 450 mA. It besides a diode 1N4148 is used as the temperature sensor, that due to its characteristics that cause it to change its resistance with temperature change....

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Door Opening Alarm with Sound Alert

The door opening alarm circuit or “Front Office Visitor Alert” is used for alerting you when a customer is at your office/shop. It will produce a beep sound when each new customer or visitor is entering, and will automatically switch OFF after few seconds.Door Opening Alert Circuit Diagram: In this circuit timer IC NE555 is used as monostable...

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