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AN-829: Environmental Compensation on the AD7142: The Effects of Temperature and
Humidity on Capacitance Sensors - AN-829 Analog Devices Application Notes
(app note added 6/06) |
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Attenuators Nullify Temperature Deviations - 08/17/98 EDN-Design Ideas:
(design idea added 6/06) |
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Auto-Fan automatic temperature Control - (Tony van Roon's circuit added 9/04) |
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Bang Bang Thermostat is Simple & Efficient - 11/06/97 EDN-Design Ideas:
Perhaps the simplest and oldest feedback loop is the nonproportional, all-or-nothing,
"bang-bang" thermostat. Fully turning on a heater when the temperature is below
setpoint and off when it's above setpoint is a straightforward example of a
servomechanism. Yet, elementary and crude as servomechanisms are, examples surround us
in virtually every household-room thermostat, clothes dryer, oven, and aquarium
heater, to name a few. The version in Figure 1 preserves the best features of the old
bang-bang: low cost, simplicity, and efficiency combined with setpoint
stability.....(design idea added 10/04) |
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Boost Converter Controls 12 Volt Fan from 5 Volt Supply - 12/12/97 EDN-Design
Ideas: --Temperature-controlled PWM boost converter allows operation
of a12V brushless dc fan from a5V supply.....(design idea added 3/03) |
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Circuit compensates optocoupler temperature coefficient - 11/22/01 EDN-Design
Ideas: When using an optocoupler in a linear application, you should consider
its gain drift with temperature. Traditional singleand dual-transistor-output devices
have a notable gain drift with temperature. In recent years, some
temperature-compensated optocouplers have appeared. However, another option is to use
two optocouplers or a dual optocoupler with appropriate feedback to make the dri.....(design
idea added 1/05) |
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Circuit Controls Multiple Thermoelectric Coolers - 08/19/99 EDN-Design Ideas:
Optoelectronic and other components sometimes use a thermoelectric cooler and a
thermistor for temperature control. A typical thermoelectric cooler.....(design idea
added 6/06) |
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Circuit generates Fan speed Control - 03/21/02 EDN-Design Ideas:
Fan noise is becoming a significant issue as electronic equipment increasingly enters
the office and the home. Noise is proportional to fan speed, and the airflow hence,
fan speed necessary for cooling is less at low ambient temperatures. Because ambient
temperature is lower than the upper design point most of the time, a fan can run
slower,.....(design idea added 10/03) |
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Circuit improves on temperature measurement - 05/02/02 EDN-Design Ideas:
When current pulses with a stable IHIGH/ILOW ratio modulate a semiconductor junction,
the ensuing voltage difference (for example, ΔVBE for a bipolar transistor)is a linear
function of the absolute (Kelvin)temperature, T. You can use this truism to make
accurate temperature measurements. Technical literature has thoroughly covered
the.....(design idea added 10/03) |
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Cold Activated Switch - The thermistor used has a resistance of 15k at 25 degrees
and 45k at 0 degrees celsius. A suitable bead type thermistor is found in the Maplin
catalogue. The 100k pot allows this circuit to trigger over a wide range of
temperatures. A slight amount of hysteresis is provided by inclusion of the 270k
resistor. This prevents relay chatter when temperature is near the switching threshold
of this circuit. (added 2/06) |
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Cold Activated Switch (Andy Collinson) - A simple thermistor triggered cold switch
with adjustable threshold. (added 10/05) |
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Constant Temperature Circuit - This circuit is a generic low power temperature
controller that can be used for stabilizing temperature sensitive electronic circuits.
It was built to stabilize a radio frequency VFO (Variable Frequency Oscillator) for
ham radio applications. The circuit has also been used to lower the drift of a Ramsey
FM10a micropower FM transmitter.....(electronic schematic / circuit added 4/02) |
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Controller Provides Closed Loop Temperature Regulation - 05/08/97 EDN-Design
Ideas: (design idea added 3/03) |
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Current and temperature ratings - Coilcraft Power Magnetics Application Note (app
note added 6/06) |
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Digital Thermostat with LED Temperature Display - I needed to replace two old,
unreliable thermostats for controlling the heating and cooling for a large garden
shed. Commercial basic digital thermostats are available quite cheaply, but some lack
the ability to control heavy loads or have the extra features that I require for
saving energy when the door is often left open or to indicate temperature being out of
range etc. I like the PIC18F1320 microcontroller used in my previous project, so
decided to use it again in a very similar design to drive three multiplexed LED
displays and read the temperature from a Dallas/Maxim DS18x20 "1-Wire" digital sensor.
….(design added 11/08) |
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Dual Comparator - forms temperature-compensated proximity Detector (app note added
5/02) |
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Electronic Thermostat Relay Circuit - Here is a simple thermostat circuit that can
be used to control a relay and supply power to a small space heater through the relay
contacts. The relay contacts should be rated above the current requirements for the
heater. Temperature changes are detected by a (1.7K @ 70F) thermistor placed in series
with a 5K potentiometer which produces about....(electronic schematic / circuit added
4/02) |
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Eliminate thermoelectric EMF in Low ohm measurements - 06/13/02 EDN-Design Ideas:
When two different-metal conductors connect together in a loop and one of the
junctions is at a higher temperature than the other, an electrical current flows
through the loop. The magnitude of this current depends on the type of metals involved
and the temperature differential of the junctions. When you open such a loop, a
thermoelectric voltage.....(design idea added 1/05) |
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Embedding Temperature Information in the ADXL202's PWM Outputs - AN-600 Analog
Devices Application Notes (app note added 6/06) |
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Environmental Compensation on the AD7144 - AN-829 Analog Devices Application Notes
(app note added 6/06) |
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Fan control - As we begin to enjoy those lazy hazy days of summer, the most
important thing on most of our minds is how to keep cool during those hot days. For
some of us that means turning up the old air conditioner and sipping on a nice cold
glass of our favorite soft drink. However, we often forget about an equally
important.... (electronic design added 6/07) |
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Fan Controller Adapts to System Temperature - 09/25/97 EDN-Design Ideas: Any
piece of electronic equipment--whether it be a lab instrument, an audio amplifier, or
a PC--that relies on a cooling fan to control internal temperature is a potential
source of noise pollution or even hearing damage. Most of the time, the fan's noise
level is probably much higher than necessary, because it has enough capacity
to.....(design idea added 2/03) |
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Freezer Over-Temperature Alarm - This electronic hobby circuit below is designed
to activate a beeper alarm, whenever the outside air temperature is below 0 degrees C
(32F). A 9v battery powers the hobby circuit. The average 9ua current is
so low that the battery should last for many years.... |
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Freezing Temperature Alarm - This circuit turns on a beeper whenever the outside
air temperature is less than zero degrees Centigrade. The circuit draws only a
few microamps from a 9 volt battery. It uses a glass bead thermistor accurate to
1 degree C. |
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Fridge door Alarm - Beeps if you leave open the door over 20 seconds. 3V
battery operation, simple circuitry. (circuit added 9/04) |
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Frost Alarm (Andy Collinson) - The thermistor used has a resistance of 15k at 25
degrees and 45k at 0 degrees celsius. A suitable bead type thermistor is found in the
Maplin catalogue. The 100k pot allows this circuit to trigger over a wide range of
temperatures. A slight amount of hysteresis is provided by inclusion of the 270k
resistor. This prevents relay chatter when temperature is near the switching threshold
of this circuit. (added 2/06) |
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Heating System Thermostat - Controlled by indoor and outdoor temperature.
Simple, high reliability design. (circuit added 9/04) |
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Improving Temperature, Stability, and Linearity of High Dynamic Range RMS RF Power
Detectors - AN-653 Analog Devices Application Note (app note added 6/06) |
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Isolation Techniques for Signal Conditioning - National Semiconductor Application
Note (app note added 2/06) |
