Ultra-large capacity capacitor power supply circuit

The use of solar cells to provide energy is inseparable from devices that store electrical energy, such as batteries. With the advancement of ultra-large-capacity capacitor manufacturing technology, small-sized and large-capacity capacitors have been produced, and their capacity has reached the farad level, making the use of capacitors to store electrical energy practical.

This test uses solar cells to provide power for the alarm device, and uses the electric energy stored in the capacitor to provide short-term high electric energy to the power output stage, forming an alarm equipment that does not require batteries or mains power, and is suitable for warning when no one is at home during the day.

The circuit is shown in the figure, which consists of a power supply circuit, a pyroelectric infrared human body detection circuit, a barking sound generating circuit, and a power amplifier circuit. The pyroelectric infrared human body detection circuit uses a commercially available human body sensor lamp, using its internal relay normally open contact; the dog barking circuit uses a finished voice chip; the power amplifier uses a Class B power amplifier board with a maximum output power of 2W. In order to operate under low voltage To obtain a large output current, use a low-impedance 3Ω paper cone speaker as the load. Its power supply circuit is introduced below.

The solar cell chooses a 25cm×25cm silicon monocrystalline panel with a nominal value of 12V/250mA, so that the output capability of 12V and 60mA can be guaranteed on cloudy days.

Capacitor selection: There are only three types of capacitors: 56F (Farad)/2.3V, 1F/5.5V, and 0.47F/11V. Of course, the larger the capacity, the better. However, due to the need for circuit working voltage, only the 0.47F/11V variety can be used. , its diameter is only as thick as a finger. In the figure, D1 is an anti-reverse flow diode; D2 is an 11V voltage regulator tube, which limits the voltage across the energy storage capacitor C1; D3 is an 8.2V voltage regulator tube. When the capacitor C1 is fully charged, D3 breaks down and conducts, causing T1 to 1ED lights up when turned on, indicating that the capacitor is fully charged. The three-terminal voltage regulator IC1 provides 5V voltage to the human body detector, and the output voltage of the solar cell supplies power to the dog barking circuit and the power amplifier circuit through the relay contact J inside the human body detector.

When the human body detector detects that someone is approaching, its normally open contact J is closed, the subsequent circuit is powered, and the speaker makes a barking sound. At this time, the capacitor C1 provides the required high power to the power amplifier circuit.

After testing, when triggered once, the contacts of the human body detector are closed for about 10 seconds. During this period, the horn emits a low and loud bark. If you are not aware of it, you will definitely panic; after 10 seconds, it returns to the alert state. At this time, the large solar battery charges C1 again. Depending on the weather, the time to fully charge (1ED lights up) varies between tens of seconds.