This document discusses current sources and their conversion to voltage sources. It defines a current source as a circuit element that maintains a constant current regardless of the voltage across its terminals. An ideal current source supplies infinite energy and constant current independent of the load. A practical current source can be modeled as an ideal source with an internal resistance. Current sources can be connected in parallel, where the total current is the sum or difference of individual currents. A voltage source is constant and independent of current drawn, while a practical voltage source has internal resistance causing voltage drop. A voltage source can be converted to a current source by modeling its internal resistance in series, and vice versa.

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2. CURRENT SOURCE METHOD
Submitted by: Submitted to:
Abdul Ahad , 20685 Dr. Fayyaz Ahmad
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3. CONTENTS
• Introduction
• Current Source
• Voltage source
• Voltage Source to Current source conversion
• Current Source to Voltage source conversion
• References
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4. SOURCE
• A Source is a device which converts mechanical, chemical, thermal or some other
form of energy into electrical energy. In other words, the source is an active
network element meant for generating electrical energy.
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6. CURRENT SOURCES
• A Current Source is an active circuit element that is capable of supplying a constant current
flow to a circuit regardless of the voltage developed across its terminals.
• As its name implies, a current source is a circuit element that maintains a constant current
flow regardless of the voltage developed across its terminals as this voltage is determined
by other circuit elements.
• There are no reliable current sources are available. The current source can be
made by putting a very high resistance in series with a voltage source.
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7. IDEAL CURRENT SOURCE
• An ideal current source may supply infinite amount of
energy.
• Then an ideal current source is called a “constant
current source” as it provides a constant steady state
current independent of the load connected to it
producing an I-V characteristic represented by a
straight line. As with voltage sources, the current
source can be either independent (ideal) or dependent
(controlled) by a voltage or current elsewhere in the
circuit, which itself can be constant or time-varying.
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8. • Ideal independent current sources are typically used to solve circuit theorems and for circuit analysis techniques
for circuits that containing real active elements. The simplest form of a current source is a resistor in series with
a voltage source creating currents ranging from a few milli-amperes to many hundreds of amperes. Remember
that a zero-value current source is an open circuit as R = 0.
• The concept of a current source is that of a two-terminal element that allows the flow of current indicated by
the direction of the arrow. Then a current source has a value, i, in units of amperes, (A). The physical
relationship between a current source and voltage variables around a network is given by Ohm’s law as these
voltage and current variables will have specified values.
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9. PRACTICAL CURRENT SOURCE
• A practical or non-ideal current source can
be represented as an ideal source with an
internal resistance connected across it. The
internal resistance (RP) produces the same
effect as a resistance connected in parallel
(shunt) with the current source as shown.
Remember that circuit elements in parallel
have exactly the same voltage drop across
them.
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10. PARALLEL ADDING CURRENT SOURCES
• Connecting two or more current sources
in parallel is equivalent to one current
source whose total current output is
given as the algebraic addition of the
individual source currents. Here in this
example, two 5 amp current sources are
combined to produce 10 amps as
𝐼𝑇 = 𝐼1 + 𝐼2
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11. PARALLEL OPPOSING CURRENT SOURCES
• Here, as the two current sources are connected in opposite directions
(indicated by their arrows), the two currents subtract from each other
as the two provide a closed-loop path for a circulating current
complying with Kirchoff’s Current Law, KCL. So for example, if the two
currents are of different values, 5A and 3A, then the output will be the
subtracted value with the smaller current subtracted from the larger
current. Resulting in a 𝐼𝑇 of 5 – 3 = 2A.
• We have seen that ideal current sources can be connected together in
parallel to form parallel-adding or parallel-opposing current sources.
• What is not allowed or is not best practice for circuit analysis, is
connecting together ideal current sources in series combinations.
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12. IDEAL VOLTAGE SOURCE
• A voltage source is a two-terminal device
whose voltage at any instant of time is
constant and is independent of the current
drawn from it. Such a voltage source is
called an Ideal Voltage Source and have
zero internal resistance.
• The example of voltage sources is
batteries and alternators.
• Practically an ideal voltage source cannot
be obtained.
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13. PRACTICAL VOLTAGE SOURCE
• Sources having some amount of internal
resistances are known as Practical Voltage
Source. Due to this internal resistance;
voltage drop takes place, and it causes the
terminal voltage to reduce. The smaller is
the internal resistance (r) of a voltage
source, the more closer it is to an Ideal
Source.
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14. VOLTAGE SOURCE TO CURRENT
SOURCE CONVERSION
• Assume a voltage source with terminal
voltage V and the internal resistance r. This
resistance is in series. The current supplied
by the source is equal to:
𝐼 = 𝑉/𝑅
when the source of the terminals are
shorted.
• This current is supplied by the equivalent
current source and the same resistance r
will be connected across the source. The
voltage source to current source conversion
is shown in the following figure.
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15. CURRENT SOURCE TO VOLTAGE
SOURCE CONVERSION
• Assume a current source with the
value I and internal resistance r.
Now according to the Ohm’s law,
the voltage across the source can be
calculated as
𝑉 = 𝐼𝑅
• Hence, voltage appearing, across
the source, when terminals are
open, is V.
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16. REFERENCES
• https://www.electronics-tutorials.ws/dccircuits/current-source.html
• https://circuitglobe.com/voltage-source-and-current-source.html
• https://en.m.wikipedia.org/wiki/Current_source
• https://www.electrical4u.com/source-of-electrical-energy/
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