# Familization with power supply and multimeter

Objective:

• how to use different types of power supply and multimeter.
• finding the error by comparing measured value and calculated value.

Theory:

DC POWER SUPPLY: – Dc power supply means direct current. In any circuit which operates from a steady voltage source, such as battery, current flow is always same direction. Every constructional project designed in design electronics works in this way. The regulated power supply is an embedded circuit. It converts unregulated AC supply to DC. Its function is to supply a stable voltage, to a circuit that must be operated within a certain power supply limits. The output is nearly always DC (direct current).

MULTIMETER: – Multimeter is an electronic device that is used to make a various electrical measurement, such as AC voltage an and DC voltage, current, resistance. It is called a multimeter. Because it combines the function of a voltmeter, ammeter and ohmmeter. Multimeter may have other functions such as, diode test, continuity test, transistor test, frequency test etc. A multimeter has three parts—1) Display, 2) Selection knob, 3) ports. The display usually has four digits and the ability to display a negative sign. A few multimeters have illuminated displays for better viewing in low light situations. The selection knob allows to save the multimeter two different things such as mA of current, voltage and resistances. Two probes are plugged into two of the ports on the front of the unit. COM stands for common and is almost always connected to ground of a circuit. 10A is the special port used when measuring large currents (greater than 200mA).

Apparatus Table:

 SL.NO NAME OF COMPONENT QUANTITY MAKERâ€™S NAME RANGE 1 Regulated DC power supply 1 2 Multimeter 1

Observation Table:

Across 0-32V for 1st channel-

 SL.NO DISPLAY READING(C.V) (Volt) MEASURED VALUE(M.V) (Volt) Error%=(C.V-M.V)/C.V*100 1 2 3 4 5

Across 0-32V for 2nd channel-

 SL.NO DISPLAY READING(C.V) (Volt) MEASURED VALUE(M.V) (Volt) Error%=(C.V-M.V)/C.V*100 1 2 3 4

Across 0-5V for fixed value-

 SL. NO DISPLAY READING(C.V) (Volt) MEASURED VALUE(M.V) (Volt) Error%=(C.V-M.V)/C.V*100 1 2

Across 0-(-ve)12V for fixed value-

 SL. NO DISPLAY READING(C.V) (Volt) MEASURED VALUE(M.V) (Volt) Error%=(C.V-M.V)/C.V*100 1 2

Across 0-12V for fixed value-

 SL. NO DISPLAY READING(C.V) (Volt) MEASURED VALUE(M.V) (Volt) Error%=(C.V-M.V)/C.V*100

Conclusion:

1) There are some error in multimeter while measuring.

2)There are some fluctuation.

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