HIGH POWER MEASUREMENT

By Calorimetric method

About the method..

• Measured by calorimeter

• Microwave Heat energy

• Heat absorbed by fluid then measuring the

temperature rise

Types

• Direct method:

Heat can be observed by rise in the

dissipating medium

• Indirect method:

Heat transferred to other medium then

measured.

Type of measuring meter

»Static calorimeter

»Circulating calorimeter

• Static calorimeter:

• it consist of 50𝞨co-axial cable, filled

with dielectric load whose hysteresis loss is

high.

• Average power input is:

• P= watts

• m = mass of the thermometric medium in gms

• = its specific heat in cal/gms

• T= temperature rise in degree celsius

• T= time in sec.

**

Circulating calorimeters

P= 4.187 v d Cp T watts

Limitation

• Thermal inertia caused by lag between

application of microwave and parameter

readings.

• Thermal inertia- the degree of slowness with which the temperature of a body approaches that of its surroundings