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Air Flow Detector #1:
This simple circuit uses an incandescent lamp to
detect airflow. With the filament exposed to
air, a constant current source is used to
slightly heat the filament. As it is heated, the
resistance increases. As air flows over the
filament it cools down, thus lowering its
resistance. A comparator is used to detect this
difference and light an LED. With a few changes,
the circuit can be connected to a meter or ADC
to provide an estimation on the amount of
airflow. |
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Air Flow Detector #2:
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Airflow Monitor Protects
Components:
09/28/95 EDN-Design Ideas |
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Electronic air flow detector:
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Linear pitot-tube air-speed
indicator:
06/09/97 Electronic Design - Ideas for Design /
Among the many methods used for measuring air
speed, one approach excels in applications
related to aerodynamics and wind power: the
Pitot-tube impact-pressure air-speed indicator.
The so-called “impact” or “stagnation” pressure
exerted by airflow. . . |
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Low-Power Solid-State Airflow
Detector:
01/22/01 Electronic Design - Ideas for Design /
Explicit airflow detection is essential in many
applications. High power-density electronics are
liable to overheat and self-destruct when
cooling-fan failures go unnoticed. Heating and
air-conditioning systems often incorporate
multipoint. . . |
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Low-power thermal airspeed sensor:
05/25/98 Electronic Design - Ideas for Design /
Among the techniques available to measure
airspeed, thermal anemometry has the virtues of
simplicity and easy miniaturization. Such
anemometers use the relationship between
airspeed and power dissipated by a heated sensor
known as King’s Law. One good. . . |
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Series-Connected Transistors Use
Differential Heating To Sense Airflow:
05/07/01 Electronic Design - Ideas for Design /
Among the methods available for airflow
measurement, thermal flow meters enjoy the
virtues of simplicity. They also offer simple
construction, low cost, and superior sensitivity
to low flow rates (less than 1000 fpm). All
thermal anemometers make. . . |
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Simple Circuit Detects Airflow:
12/04/00 Electronic Design - Ideas for Design /
Moving air provides a better conductive path and
cooling method for hot components than stagnant
air. Therefore, airflow is a critical parameter
in systems where heat build-up is a concern. The
circuit shown is unique because it wasn’t
designed to. |
