This article descripts, how I built amplifier from Mr. Marshall Leach known like "The Leach Amp". I built amplifier from the original instructions on these pages: http://users.ece.gatech.edu/~mleach/lowtim/. Article about bulding of this amplifier I found later in journal A_Radio Praktická elektronika 11/2002. For many years I looked for construction of HiFi amplifier wit a good parameters, enough power reserve and simple construction.
The Leach amp 200W amplifier - [Link]
This project uses 2 AA size rechargeable NiMH batteries (1.2V 600mAH) being recharged by the solar panel and also has a conventional battery holder for 2 more AA size cells in parallel with the rechargeable ones. Thus, if the conventional cells are low you may always recharge the other battery holder. Suggested uses for this torch are: bike, car and at home. [via]
White LED flashlight - [Link]
Here's an inexpensive electronic circuit that you can build to put in your Jack-o'lantern. It provides power to drive a few LEDs at night, and automatically turns them off during the daytime. It's a simple and automatic dark-detecting circuit that you can use to for your very own photosensitive pumpkin.
Dark detecting circuit - [Link]
In this flashlight, each LED/resistor combination consumes 4.5volts at 30mA or about 135mWatts. The ballast resistor alone consumes 1.1volts at 30mA or about 33mWatts. Therefore, 25% of the power being drained from the batteries is lost in the resistor of each LED chain. [via]
A low power, long life LED flashlight circuit - [Link]
Mark: To keep the lights on and the camera going I have a multi-purpose battery charger. This contains around 24Wh of energy storage in eleven NiMh AA cells and circuitry to charge my laptop, satellite phone, mobile phone, camera battery and a PP3 for Ju's Dog Dazer. It can also power a white LED tent light that sheds just about enough light to cook by. A cunning design means that some of the AA cells can be removed from the internal battery stack and exchanged with flat ones from a torch or whatever. [via]
Multi-purpose charger - [Link]
