2. At the end of the competition, the participating teams should submit the following materials: (1) Design Report; (2) Making physical objects; (3) Registration Form of 2007 National College Students Electronic Design Competition. The above materials are sealed into cartons provided by each school using seals made by the competition area.
3,When the light becomes weak, the resistance becomes larger, the 5-pin potential decreases, the unsteady oscillation frequency increases, and the LED flash frequency naturally accelerates.
5, the principle of using a triode to control the LED light so that it flashes at a fixed frequency is to use a triode and a resistor and a capacitor to form an oscillation circuit, and the load is LED.
It can be seen that the fundamental cause of LED power input current distortion is the use of DCFilter electrolytic capacitors due to capacitive load. FIG. 2 For the non-sine wave that distorts the input current of the LED driver power supply, Fourier series must be used to describe it.
Because the voltage of the ordinary LED tube can work at about 0-3, the current is about 0.1-0.2A, but the brightness has a large change. That's the main reason. In fact, to save energy, it is more reasonable to make a general 3-9 tube series circuit, and the corresponding voltage is 111226.
220v AC input; F1 is the fuse; c1 is a high frequency filter capacitor, which is equal toL1 inductors together in order to make the input sine wave frequency more single, play a role in filtering the peak pulse. 2, and then through the rectification bridge D1 rectification and the electrolytic capacitor c2 filtering to get about 300v direct current.
1, if the output voltage of the LED switching power supply is 0, it may cause the LED lamp to not work properly. This fault is usually caused by a short circuit or open circuit at the output of the power supply.
2, the input voltage is unstable: checkThe power input voltage is normal. Output voltage is unstable: Check whether the output voltage of the power supply is normal. Short-circuit fault: Check whether there is a short circuit at the output end of the power supply. Overload fault: Check whether the power output is overloaded. If the temperature is too high, check whether the heat dissipation of the power supply is normal.
3, LED flat light driver power is a common lighting equipment, its working principle is to convert alternating current into direct current to supply LED light strip work. However, after a long time of use, the flat light driving power may fail and need to be repaired. First, we need to check the cable connection of the drive power supplyNo loose or damaged.
4, LED special switching power supply is a power supply equipment commonly used in LED lamps, but sometimes there may be a failure to work normally. The first step in repairing a fault is to check the power supply. Ensure that the power supply is in good contact and that the line is not short-circuited or disconnected.
5, due to the start of the power grid load and the induction of lightning strikes, the power grid system will invade a variety of surges, and some surges will cause damage to the LED. Therefore, the analysis of the power supply has a certain lack of surge protection, and as for the frequent replacement of the power supply and lamps, the LED driver power supply should have the suppression of surge intrusionThe ability to protect the LED from being damaged.
1, T2 on, T3 off, charge the battery, charging indicator LED2 light. Current limiting charging: If the charging current is greater than the limit value, the voltage at both ends of the current sampling resistor R7 increases, the BE electrode voltage of the triode T3 is higher than the dead zone voltage, and the monostable trigger state is triggered.
2, nickel-metal hydride battery charger schematic: composed of LM324, with TL431 set voltage baseCorrect, use S8550 as the regulating tube, the input voltage is reduced, and the battery is charged, as shown in the circuit diagram. The working principle is: the reference voltage Vref is formed: the external power supply is filtered by the capacitor C1 after the socket X and the diode VD1.
3, the maximum charging current of the electric bicycle charger is mostly about 2A. Electric bicycle charger using switching power supply technology (1) Shandong GD36 charger circuit schematic diagram is shown in Figure 12.
4, schematic diagram: charger (charger) according to the design circuit working frequency to divide, can be divided into power frequency machine and high frequency machine. <5, lithium battery charging circuit principle Lithium battery and nickel-cadmium, nickel-metal hydride rechargeable battery: the negative of lithium-ion battery is graphite crystal, and the positive electrode is usually lithium dioxide. During charging, lithium ions move from positive to negative and are embedded in the graphite layer. During discharge, lithium ions move from the negative surface of the graphite crystal to the positive electrode.
1, AND door, ANTENNA, BATTERY DC power supply, BELL, bell, BVC sameAxle cable connector, BRIDEG 1 rectifier bridge (diode), BRIDEG 2 rectifier bridge (integrated block), BUFFER buffer, BUZZER buzzer, CAP capacitor.
2, Proteus switch components names are relays, transistors, switches, multiplexers, photoelectric relays, sensor switches and so on. Relay Relay is a common switching component, by controlling the electromagnetic coil on and off to achieve the switch between open and close contacts, used to control high voltage and high current switching operation.
3,". Select a device, click "Detail report" in the upper right corner, and the "Report Window" will pop up to provide detailed data of the device. There is a bidirectional voltage regulator in the library - BZB100A, its stable voltage is 100V, if you need other voltages, two regulator tubes can be used in series.