LM3647 Reference Design

The LM3647 provides a single-chip charge management solution for Nickel Cadmium, Nickel Metal Hydride and Lithium-Ion cells. The device handles the entire charging process from rejuvenating deeply discharged cells to providing a number of charge termination and maintenance options. The LM3647 Demo Board allows users to create a battery charging solution with little effort.

Link : http://www.national.com/an/AN/AN-1165.pdf

7.2 Volt Field Charger

The unit is novel as it’s display graph shows you the time the battery has been charging in 2 minute intervals up to 16 minutes when finished.... read more

Self-heated transistor digitizes airflow

A sensitive and reliable way to measure airflow is to exploit the predictable relationship between airspeed and the heat dissipated by a sensor exposed to the flow while being held at a constant temperature differential above ambient. The power required to maintain the elevated sensor temperature is proportional to the square root of the airspeed (King's law). The popular hot-wire anemometer uses this principle, but suffers from the disadvantage of using a relatively fragile airflow sensor, a thin metallic filament.

Link source: http://www.edn.com/archives/1996/031496/06di3.htm
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Transistor and FVCs make linear anemometer

A previous Design Idea presented a simple flow-to-frequency transducer that easily fits into mP-based measurement systems (Reference 1). You can accumulate and linearize its frequency output by using software without the need for ancillary circuitry. In other applications, however, you might prefer a linearized analog output.

Link source : http://www.edn.com/archives/1996/092696/20di4.htm
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