The author encountered a problem with a microcontroller system in which the +5-V supply voltage did not decay to 0 V sufficiently quickly after being switched off. A certain residual voltage... Read more
This circuit may be used to replace the single current limiting resistor often found in dirt cheap battery chargers. The alternative shown here will eventually pay off because you no longer... Read more
It is impossible to imagine a present-day society without any batteries. Count the number of gadgets in your house that are powered by batteries, you will be stunned by the number of batteri... Read more
This mini pocket torch combines the advantages of Lithium button cells with a super-bright white LED. The lithium cells are small, have a long shelf life and have very little self-discharge.... Read more
The use of solar photovoltaic (PV) energy sources is increasing due to global warming concerns on the one hand, and cost-effectiveness on the other. Many engineers involved in power electron... Read more
Your everyday 7805 regulator is not the best choice for powering accurate measurement circuits and A/D converters, mainly because it generates too much noise, and exhibits spurious behavior... Read more
Smoke alarms are extremely useful devices, but they suffer from one significant disadvantage, which is that they’re battery powered. This can’t really be avoided since a smoke alarm should s... Read more
The author found that a long-neglected gel battery in a hand-held vacuum cleaner had gone high-resistance. It took some effort to make it usable again, by alternately applying voltages of op... Read more
If you’ve read old textbooks on electronics basics you may recall how it’s possible to create a multivibrator from just a neon lamp and a capacitor. The circuit of the simple multivibrator s... Read more
It takes up to an hour for our eyes to fully adapt to the dark and achieve maximum light sensitivity with the iris fully open. Astronomers use red light to avoid interfering with this adapta... Read more
