Novel and practical solar charging night light

LED light-emitting diode

The solar charging night light has novel functions and simple circuit. It is charged in the sun during the day and can be used at night. It is very convenient and is very suitable for the production of electronic enthusiasts.

1. Circuit working principle

The solar charging night light electric schematic is shown above. The solar cell GB1 receives sunlight to generate electricity during the day, and charges the nickel-cadmium battery GB2 through VD1. The schematic diagram of the utility circuit is shown below. When the solar cell GB1 generates voltage, GB1>GB2, charge the nickel-cadmium battery GB2 and store energy. At this time, VT1 is turned on, VT2 is turned off, and the LED of the light-emitting tube is not lit. After dark, GBl

2. Component selection and testing

The triode VT1 and VT2 are 8050, and the characteristic parameters are shown in the following table. Diode VD1 selects 1N4001. The LED model of the LED can be used as a general tube, as long as the forward conduction voltage is in the range of 1.5 to 2.5V. The resistance R1 is 1.5 kΩ, R2 is 100 kΩ, and R3 is 2 kΩ, and the above resistances are all 1/8 W metal film resistors. The solar cell GB1 is 4.5V, 70mA, and the nickel-cadmium battery GB2 is a 1.5V nickel-cadmium rechargeable battery.

The detection of transistors, LEDs and resistors is relatively simple, and many others have been described in other reference books. Only the detection method of the solar cell will be described below. Solar cells, also called silicon photocells, are optoelectronic devices that convert light energy into electrical energy. The basic structure of a solar cell is a large-area PN junction. Under the illumination of light, an electromotive force can be generated at both ends of the PN junction, and a current is formed when the load is connected. In addition to the special tester for accurate detection, the solar cell detection method can also be easily detected by a multimeter. The specific method is: dial the multimeter to the RXlkΩ file, the red pen is connected to the positive electrode of the solar cell, and the black test pen is connected to the negative electrode. When the solar cell is placed in a dark place, the resistance of the resistor should be ∞; when it is close to the 60W incandescent lamp, the resistance value will be rapidly reduced to about 12kΩ. Such a solar cell is good and can be used.

Third, the production method and instructions for use

The shape of the solar charging night light is shown on the right. When making this circuit, choose a commercially available (or homemade) smoke alarm plastic case, install a square solar cell (4.5V, 70mA) on top of it, and install two 5th battery clips and automatic charge/discharge circuit control board. A light-emitting diode is soldered on the board to indicate the working state of the circuit.

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