亮度控制小灯电路

亮度控制小灯电路--Brightness Control for small Lamps

Switching operated 1.5V bulbs
Portable unit, 3V battery supply
Parts:

P1________________470K Linear Potentiometer

R1_________________10K 1/4W Resistor
R2_________________47K 1/4W Resistor (See电感生产厂家 Notes)
R3__________________1K5 1/4W Resistor

C1_________________22nF 63V Polyester Cap工字电感acitor
C2________________100΅F 25V Electrolytic Capacitor

D1,D2___________1N4148 75V 150mA Diodes

IC1_______________7555 or TS555CN CMos Timer IC

Q1___________模压电感____BD681 100V 4A NPN Darlington Transistor

LP1_______________1.5V 200mA Bulb (See Notes)

SW1_______________SPST Switch

B1__________________3V (Two 1.5V AA or AAA cells in series, etc.)

Circuit operation: led

This device was designed on request, to control the light intensity of four filament lamps (i.e. a ring illuminator) for close-up pictures with a digital camera, powered by two AA or AAA batteries. Obviously it can be used in other ways, at anyone's will.
IC大功率电感贴片电感器1 generates a 150Hz squarewave having a variable duty-cycle. When the cursor of P1 is fully rotated towards D1, the output positive pulses appearing at pin 3 of IC1 are very narrow. Lamp LP1, driven by Q1, is off as the voltage across its leads is too low. When the cursor of P1 is rotated towards R2, the output pulses increase in width, reaching their maximum amplitude when the potentiometer is rotated fully clockwise. In this way the lamp reaches its full brightness.

Notes:

LP1 could be one or more 1.5V bulbs wired in paralle电感器图片l. Maximum total output current allowed is about 1A.

R2 limits the output voltage, measured across LP1 leads, to 1.5V. Its actual value is dependent on the total current drawn by the bulb(s) and should be set at full load in order to obtain about 1.5V across the bulb(s) leads when P1 is rotated fully clockwise.

用品胜的移动充电宝给单片机开发板供电问题请问下，我用品胜的移动充电宝给单片机开发板供电，每次都只能工作一分钟左右就自动断电了，开发板重新开机也不行，只能移动充电器重新插拔，请问这是什么原因呢？换了同型号的移动充电宝、开发板后，现象也一样，排除硬件损坏问题。     移动充电宝的最大电流据标称是2.4A，开发板上只用到52单片机和1602液晶屏。 消耗电流太小，充电宝以为 已经充饱电，自动断电。   接个假负载，比如一粒 47 欧的 2W 插件电阻，100mA，就应该不会自动断电了。       

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观点解析：云存储技术和电子发现相结合 首先，我们将云定义为基于云存储的技术。通常，这种定义意味着通过互联网提供可扩展的以及虚拟化的计算资源。但云不单单是这样，还有更多功能，而对于如何扩展该定义的意见也各不相同。首先，我们将云定义为基于云