Archive for May, 2008
Pb and acid batteries charger
Modern acid batteries and plates Pb, are embodiment of simplicity in use. Unlike NiCd batteries, they must be recharged by connecting to a constant voltage. In this situation, the loading current will provide a good indication of the state of loading.
These batteries can be quickly loaded as long as the loading current is [...]
Preselector for SW receivers
The entry low capacitance of MOSFET modern, with two gates, will create negative inverse reaction through a uncoupled source resistor. Applied right this technique allows the creation of a entrance RF stage field with a relatively high dynamic range.
Radio amateur working on short wave: there is no need to tell, in the days of our [...]
Electronic mosquito
The circuit behaves like a true mosquito: once the light dims, the mosquito starts an annoying buzz. When its light again it becomes mute, so that, as in the case of genuine mosquito is very difficult to spot.
Tension from pin 2’s IC1a determines if mosquito is active or not. The level of this [...]
