November 25, 2018


At these high frequencies, filter capacitor C 1 does not need to be very large, a 0. Compact florescent lamps are available in places, and as Wolfgang pointed out, they eventually wear out and need replacement. In full sunlight the panel is specified to produce 4. The inductors were wound on three types of cores, which are a bobbin core oed, covered in heat shrink tubinga toroid core center and an E-E core, right. On the back of the panel are two thin solderable terminals, with marked polarity. The CE input includes a small pull-up current. New on this site since original publication of this page in

Uploader: Nezil
Date Added: 5 June 2009
File Size: 42.94 Mb
Operating Systems: Windows NT/2000/XP/2003/2003/7/8/10 MacOS 10/X
Downloads: 32566
Price: Free* [*Free Regsitration Required]

The inductance constant of the core physical dimensions and u mostly determine how man microseconds it takes the collector current to rise to the point the circuit switches off, and it 6608w determines how long current will be delivered to the LED when the transistor is off.

Our last circuit examples extend the previous designs by adding a small AVR microcontroller. I wound 60 turns of the twisted pair in about three layers around the ldd nail, then I connected the start end of one conductor to the finish end of the other conductor and that made it into a turn center tapped inductor.

On the toroid core, I wound 10 turns of 26 wire wrapping wire, pulled out a center tap, and wound another 10 turns. Some compact florescent lamps from Sylvania had failed in my home.

Voltage that appears from the tap on the inductor to the collector causes the voltage on the 1K resistor to be even higher than the battery voltage, thereby providing positive feedback. New on this site since original publication of this page in To finish it up, we carved a beautiful white pumpkin and added this circuit to make our microcontroller-driven, dark-detecting, solar-powered programmable pumpkin, which faded its eyes in and out one at a time.


On the back of the panel are two thin solderable terminals, with marked polarity. You might consider adding an intermediate 6608a or voltage regulator, to make sure that you can provide a steady 5 V, or whatever your phones actually require.

By adding another diode and capacitor we can generate negative output voltages as shown in figure 5. Figure 7 Adding negative feedback regulates the output voltage. The load regulation is fairly good up to the maximum current based on the chosen value for L 1 however, the temperature stability will be rather poor because of the strong negative TC of V BE.

Get a transformer core, preferably ferrite, and wind 20 turns on it. Two experimenters have provided reports of their experiences with nonmagnetic cores, each with its unique attributes.

Even though the battery voltage drops, the color of the light is always a crisp bluish-white. To reduce the component count the application of the YX chip is rather lde.

His circuit powers a white LED from a 1. A note of caution: Data sheets for several of Duracell’s alkaline cells can be found here. Please see the copyright and liability disclaimer on the HOME page. Christian Daniel of Gernany wrote, noting that the shielding beads are not idea for this kind of use, so you might want to try this last. RohrerCopying for commercial purposes is not permitted without permission of the authors. This now negative going waveform is rectified by D 2 and filtered by C 2.

Do you think I am correct?



If the core saturates before the IR drop from tap to collector approaches the battery voltage, the circuit will switch quickly anyway because saturating the core makes the coil look ler a resistor and coupling between the collector half and the base half the side with the 1k resistor drops to very little, so the effect is the same as the IR drop approaching battery voltage.

Some images copyright mrpiggss, Why would this be? What should I change in that circuit? Adding a voltage comparator to drive the CE input with feedback from the boosted output adds regulation to the circuit as in a led led DC-DC converter Lab Activity. Another option is to replace the simple inductor with a transformer.

The basic configurations in figures 2 and 3 drive the LED with pulses of current 6608a the oscillator frequency. To perform the switching, we use a PNP transistor that is controlled by the voltage output from the solar panel. My solar panel generates 7V1.


So now we have a very common source of toroids. The multiplication factor N is set by the resistor divider ratio. If you are about to toss an ldd keyboard into the recycling bin, why not cut off 6608z ferrite bead first? This circuit is suitable for powering flashlights, emergency lighting, and other applications in which it is desirable to power white LEDs from one or two primary cell batteries using a low cost circuit.