﻿ Work tasks - Load characteristic of the source
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## Load characteristic of the source

### Work Task and Measurement Procedure

1. Measure the dependence of US on the current I of two basic types of electrochemical sources (alkaline and zinc-chlorine batteries).

2. Add the obtained dependence values to the graphs US = US(I) and compare the shapes of the two characteristics with the theory.

3. Determine the basic parameters of the studied sources (electromotive voltage Ue and internal resistance Ri). Compare them with each other and determine how they relate to real source characteristics (source hardness).

4. Determine individual short-circuit currents from the obtained parameters of both sources. Compare them with values obtained by extrapolating linear regressions of the measured characteristics.

#### Measurement Procedure

1. Run the remote experiment ZACHaRIAS – Load characteristic of the source.

2. Select a type of measured source. Memorize the value of the no-load voltage corresponding to the electromotive voltage of the selected source.

3. Gradually increase the current drawn from the source by using the slider (PC) or the + and (tablets).

4. Read the value of the clamping voltage for each value of the set current – are deposited in the prepared table.

5. Continuously check the measured values in the graph, in case of larger gaps between the measured dependencies, measure the missing parts.

6. After measuring the required number of data, select another type of source and repeat the measurement.

7. Reduce the current drawn to zero after measuring the characteristics of all resources (save all experimental values), exit the remote experiment.

8. Open the experimental data file in a spreadsheet program (MS Excel, Oo Calc, Google Tabs, Kingsoft Spreadsheets…).

9. Plot the dependence of the terminal voltage on the drawn electric current (for the first source) in the graph. Check the shape of the obtained dependence with the assumed shape.

10. The best way to do this is to determine the equation obtained by the regression line (linear regression). The slope of the regression line corresponds to the internal resistance of the source – see formula (5), the absolute linear gain obtained corresponds to the electromotive voltage.

11. Determine the parameters required for the second type of source in a similar manner.

12. Determine the magnitude of the short-circuit current of both sources using the values of the electromotive voltage and the internal resistance of the source.

13. Take advantage of the ability to extend the regression line to higher values than the measured maximum currents. This can be used (based on the measured values and the assumption of a continuous linear relationship) to estimate the value of the short-circuit current – intercept current (horizontal) axis.

14. Compare the basic parameters of the investigated sources (electromotive voltage, internal resistance and zktrat current) and compare them with the real properties of the sources.