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A Galvanically Isolated Thermistor Digitizer - The LTC1799 is a precision oscillator that is easy to use and occupies very little PC board space. The oscillator frequency is programmed by a single external resistor (RSET). The LTC1799 has been designed for high accuracy operation (≤1.5% frequency error) without the need for external trim components__ Linear Technology/Analog Devices App Note, ,Mar 30th 2010 Alarm Sounds At Freezing Temperatures - 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 . . . Hobby Circuit designed by David Johnson P.E.-July, 2006
AN75 - Circuitry for Signal Conditioning and Power Conversion - Linear Technology AN75 __ Designed by Jim Williams - Mar 1st, 1999
AN98 - Signal Sources, Conditioners and Power Circuitry Circuits of the Fall, 2004 - Linear Technology AN98 __ Designed by Jim Williams - Nov 19th, 2004
Anticipator Improves On Earlier Idea - EDN Design Ideas: 05/24/2012 A self-biasing thermistor circuit had an overall dominant thermal/electrical time constant as small as 25 msec but had a significantly rounded response following a square (thermal) input pulse of 100 msec; the source was a pulsed blue LED. A single-op-amp-based “anticipator-like” circuit generated a more faithful picture of the actual input excitation, and improved on the circuit described in a previous Design ideas (Reference 1). The lowpass filter in Figure 1, with an RC time constant of approximately 25 msec, models the circuit. Design by Nicholas Lockerbie, Scottish Universities Physics Alliance, Glasgow, Scotland
Anticipator Speeds Signal Settling to a Final Value - 03/17/11 EDN Design Ideas: Use a differentiator circuit to predict the final value of an exponential signal. The circuit in this Design idea anticipates, or jumps instantly to, the final voltage of an input-signal change. it relies on the fact that the intended input signal changes exponentially with a known time constant. This circuit was adapted from a 1970s-era instant-reading electronic thermometer, which displayed a patient’s body temperature within seconds after a thermometer probe was placed under the patient’s tongue. it exploits the fact that the temperature probe’s exponential thermal response-time characteristic is known. Design by Tim Regan, Linear Technology App Note, San Jose, CA-- 03/17/11
Battery-Powered Freezer Alarm - A typical freezer can contain hundreds of dollars with of food. if the device becomes unplugged or if the door is left open too long, the food inside can quickly become spoiled. The hobby circuit below is a battery powered alarm system, which is attached . . . Hobby Circuit designed by David A. Johnson P.E.-July, 2006
Circuit Improves On Earlier Idea - EDN Design Ideas: 05/24/2012 A self-biasing thermistor circuit had an overall dominant thermal/electrical time constant as small as 25 msec but had a significantly rounded response following a square (thermal) input pulse of 100 msec; the source was a pulsed blue LED. A single-op-amp-based “anticipator-like” circuit generated a more faithful picture of the actual input excitation, and improved on the circuit described in a previous Design ideas (Reference 1). The lowpass filter in Figure 1, with an RC time constant of approximately 25 msec, models the circuit. Design by Nicholas Lockerbie, Scottish Universities Physics Alliance, Glasgow, Scotland
Circuitry for Signal Conditioning and Power Conversion - Linear Technology AN75 __ Designed by Jim Williams - Mar 1st, 1999
Determine balancing current for the LTC3305 lead-acid battery balancer - EDN Design Ideas: 06/29/2016 Delve into PTC thermistor intricacies to optimize battery-balancing designs Design by LTC Design Note
Freeze Alarm - I chose an accurate thermistor from Keystone as the temperature sensor for this circuit. This device has a very specific resistance at a particular temperature. According to the data sheet for the thermistor, the device will have a resistance of 361K at zero degrees C, which is the freezing point of water. The thermistor is wired into a simple bridge circuit, which uses 1% resistors. The bridge is connected to a very low power voltage comparator. The circuit forms a switch circuit, which changes state, when the resistance of the thermistor reaches a certain value. At zero degrees C the voltage at the non-inverting input of the comparator exceedsCircuit Solution by David Johnson P.E.-May, 2006
Freezer Over-Temperature Alarm - This circuit turns on a beeper whenever the inside temperature of a freezer is greater 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.. . . Circuit by David A. Johnson P.E.-November, 2014
Freezing Temperature Alarm - The 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 circuit. The average 9ua current is so low that the battery should last for many years.. . . Circuit by Dave Johnson P.E.-November, 2014
Heat Sensor - The Thermistor, or NTC (Tony van Roon's Negative Temperature Coefficient) of 10K, is a standard type. Most types will work. The one in the diagram is a 10K model made by Fenwal (Tony van Roon's #197-103LAG-A01) __ Designed by Tony van Roon VA3AVR
Linearize thermistors with new formula - EDN Design Ideas: 03/03/2014 Optimize thermistor performance at any preferred temperature Design by Mark Biegert
LTC Design Note: Determine balancing current for the LTC3305 lead-acid battery balancer - EDN Design Ideas: 06/29/2016 Delve into PTC thermistor intricacies to optimize battery-balancing designs Design
Pseudologarithmic thermistor signal conditioning spans wide temperature range - 6-Jan-05 EDN Design Ideas: Given its low cost, small size, robust construction, accuracy, versatility and sensitivity, it's no wonder that the thermistor rates as one of the most popular temperature sensors available. However, in some applications, a thermistor can exhibit too much sensitivity for wide-range temperature measurements Design by Stephen Woodward, University of North Carolina, Chapel Hill, NC
Sensor to Display, Built with Thermistor, 12-Bit ADC, 89S52 & LED Display - This is my student assignment for the class "Designing Microprocessor Based instrumentation". The board demonstrates the use of 12-bit ADC, writing c program with digital filtering and interface the LED display. The reading provides 0.1C sensitivity. The optional input of the ADC is available for exercise with other input signals or sensors. __ Designed by Wichit Sirichote
Signal Sources, Conditioners and Power Circuitry Circuits of the Fall, 2004 - Linear Technology AN98 __ Designed by Jim Williams - Nov 19th, 2004
Simple Circuit Anticipator Improves On Earlier Idea - EDN Design Ideas: 05/24/2012 A self-biasing thermistor circuit had an overall dominant thermal/electrical time constant as small as 25 msec but had a significantly rounded response following a square (thermal) input pulse of 100 msec; the source was a pulsed blue LED. A single-op-amp-based “anticipator-like” circuit generated a more faithful picture of the actual input excitation, and improved on the circuit described in a previous Design ideas (Reference 1). The lowpass filter in Figure 1, with an RC time constant of approximately 25 msec, models the circuit. Design by Nicholas Lockerbie, Scottish Universities Physics Alliance, Glasgow, Scotland
Temperature-to-period provides linearization of thermistor response - 11/10/05 EDN Design Ideas: Highly accurate pulsewidth varies with temperature Design by
Kaliyugavaradan, Anna University, Madras Institute of Technology, Chennai, India
Thermistor Preamp - (spice design) __ Designed by Rick
Thermistor Thermometer: LCD Version - This is the 2nd version of Thermistor Thermometer Project done by another group of my student. The 1st version having 4-digit 7-segment LED shows the use of simple display device. For applications that needs text display, this LCD version is more suitable and easy to adapt for many kinds of measuring devices. __ Designed by Wichit Sirichote
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