High Efficiency 0-100% LED Dimmer How to convert 10mA from your battery to 20mA for your LED? This webpage describes a high-efficiency LED dimmer or a dimmable LED flashlight, or a source of switching current, or whatever you want to call it. Inexpensive, single IC uses widely available parts, easy to make. It’s designed to get the longest light from a (rechargeable) battery, which is ideal in emergency situations: About 24+ hours for a single white LED at full brightness from a cheap 9V, 200mAh battery.
It works well from 4 to at least 30 Volts; The brightness level can change over time, while mainly keeping it constant. It can drive as many LEDs as is normally possible with the supplied supply voltage. The efficiency is up to 94% (*), even higher when a cunningly divided supply voltage system is used.
This webpage describes a highly efficient LED dimmer, or a dimmable LED flashlight, or a switching current source, or whatever you want to call it. Cheap, single-IC, uses commonly available parts, easy to build. Designed to get the longest light out of a (rechargable) battery, ideal in emergency situations: some 24+ hours for a single white LED at full brightness from a cheap 9V, 200mAh battery. Works well from 4 up to at least 30 Volts; may even vary over time, while the brightness level is maintained essentially constant. Can drive as many LEDs
“Practically theoretical” value for the special case when the supply voltage is fully sufficient to supply the LEDs at full brightness. The PWM is then turned on continuously (100% duty cycle) and provides a constant overhead load current of <1.2mA; The LED current is 20mA and R7 and only a little more loss in interference resistors.
PWM LED Driver Circuit
Source opensourcepartners.nl LED Dimmer Circuit files alternative link:
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Published: 2010/02/22 Tags: power electronic projects, pwm circuits
5V to 200V with NE555 DC DC Converter
The astable multivibrator using NE555 integrated timing voltage of 5 volts DC to 200 volts to 200 volts dc voltage can upgrade to the power 20 of which can be taken out
“In addition to @timpat” Adapted from my teacher useful information: transistors used in the original scheme can give bc337’n the current (at 5V) to a maximum of 800. In this case, even if we accept that it is 100% of the yield on the secondary side of the transformer 200V’t the maximum current that can be drawn: Isxvs = ıpxvp => Business = (ıpxvp) / Vs = (0.8 × 5) / 200 = 20mA will be.
5V to 200V Circuit