AS with many tinkerers and junk electronics collectors, a variety of “acquired” power supplies wind up on the author’s shelves to await attention. But are they worth keeping? Testing them with a resistive load is messy and difficult, and with high current supplies it is nearly impossible, … [Read more...]
The idea for this circuit came when I was repairing my aunt’s emergency light. Bulb based emergency lighting has a low efficiency and ultrabright l.e.d.s provide greater efficiency and more illumination, with a much extended battery life. It was therefore decided to change from a 12V light bulb to … [Read more...]
The size and shape of the robot can vary greatly, and size alone does not determine the intelligence of the machine or its capabilities. Home-brew robots are generally the size of a small dog, although some are as compact as an aquarium turtle and a few as large as Arnold Schwarzenegger. The overall … [Read more...]
THE circuit shown in Fig. must represent the limits of simplicity for a metal detector – yet the design works surprisingly well. It uses just one 40106 hex Schmitt inverter i.c., a capacitor, and a search coil – and of course the batteries. A lead from IC1b pin 4 needs to be attached to a medium … [Read more...]
New Version CadSoft Eagle Professional 6.1 is Available Now Download here If you are looking for an easy to use, powerful and affordable schematic capture and printed circuit board design package that gets the job done, EAGLE is the number 1 choice! CadSoft offers user friendly, … [Read more...]
We can increase the voltage gain still further by connecting two similar circuits as shown in Fig.. This will provide a significant increase in the gain, enabling an electronic switch, for example, to be controlled by quite low sound levels. … [Read more...]
With recent advances in semiconductor technology, the maximumluminous intensity of red l.e.d.s has increased to several candelas. Now consider that human flesh is translucent to red light. Combine these two facts, and we have the basis for the present project. The average cheek has a … [Read more...]
It is very difficult to keep track of number of balls and number of overs bowled simultaneously so in order to solve this problem we built a small Cricket Over Counter which keeps track of no balls and no of overs bowled.Whenever the legal ball is bowled the switch is pressed and it reminds when one … [Read more...]
Transistors are current amplifiers. We sometimes need a voltage amplifier – for example, to boost the small signal from a microphone to an acceptable level. Although an op.amp provides the ideal solution, a simple one or two-transistor amplifier can be very useful, particularly if the quality of … [Read more...]
Often Garden Lights are made by high watt electric bulbs which increases the power consumption ,In order to solve this problem we built a smart garden light which is built by 32 yellow LED's hence the power consumption is very Less.This smart Garden light can be set to any light intensity below … [Read more...]