Current Electricity: Calculating Power at 0 & 100 Degrees C

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SUMMARY

The discussion focuses on calculating power dissipation in a thermistor within a circuit at two temperature points: 0°C and 100°C. The thermistor has resistances of 60k ohms at 100°C and 100k ohms at 0°C, in series with a 12k ohm resistor. The correct method involves calculating total resistance, determining total current, and applying the formula P = I²R to find power dissipation. The correct power dissipation at 0°C is 4 microwatts, highlighting the importance of accurate voltage and current values in calculations.

PREREQUISITES
  • Understanding of Ohm's Law
  • Familiarity with thermistor characteristics
  • Knowledge of power calculation formulas (P = IV, P = I²R)
  • Basic circuit analysis skills
NEXT STEPS
  • Study thermistor behavior and its temperature-resistance relationship
  • Learn advanced circuit analysis techniques using Kirchhoff's laws
  • Explore power dissipation calculations in series and parallel circuits
  • Investigate the impact of ideal vs. non-ideal components in circuit analysis
USEFUL FOR

Students studying electrical engineering, educators teaching current electricity concepts, and anyone interested in circuit analysis and thermistor applications.

fran008
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I am revising the chapter on current electricity and i came across this question which i got stuck in the last part. It shows a circuit with a thermistor having a resistane of 60k ohms at 100 deg C and 100k ohm at 0 deg C. The termistor is in series witha 12 k ohm resistor There is a voltmeter but we are told that we can consider it behaving ideally. Now the last questions were: depermine the power dissipated in the thermistor at
a 100 deg C
b 0 deg C

Checking my answer for a , it was worked out rigght :). but d problem is b, i got a wrong ans when I used the same method ie

I found R total by adding the 2 resistances. Then using ratios I found voltage across the thermistor which is 10.7, then using I=V/R i found I and then used P=IV. What is wrong pls? My book says that the ans is 4microwatts
 
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You are most likely using the wrong value for voltage or current at some stage. If you could write out your calculations.

One method in doing the problem is to find the total resistance, then find the total current. To find the power dissipating through any resistor, then use [tex]P_1 = I^2 R_1[/tex].
 

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