INDUCED EMF
INDUCED EMF
Whenever a conductor is placed in a varying magnetic field, EMF is induced in the conductor and this EMF is called induced EMF.
Induced EMF is of two types
I. Dynamically induced EMF
When the conductor is in motion and the field is in stationary so the EMF is induced in the conductor, this type of EMF is called dynamically
RESISTANCE IN SERIES
RESISTANCE IN SERIES
R1, R2 and R3 are three resistance-connected end to end across voltage source, V. VI. V2 and V3 are voltage drops in RI, R2 and R3 respectively I is the total current. From the fig we see that
VT= VI+V2+V3 ---> (1)
We know that
Vs=IR—> (2)
Put eq (2) in eq (1) we get
IRT= IR1+IR2+IR3--------> (3)
IRT = I(R1+R2+R3) —>(4)
Divide both sides by I we get
RT = R1+R2+R3
In general
RT = R1+R2+R3........................... Rn
Where n=1,2,3,4,........
CONCLUSION
In series combination of resistance the total resistance
RESISTORS IN PARALLEL
RESISTORS IN PARALLEL
PARALLEL COMBINATION OF resistorS
R1, R2 and R3 are three resistors connected across voltage source V. I1, I2 and I3 are three current following in R1, R2 and R3 respectively. It is the total current of supply source, as shown in the fig.
From the fig we
Electronics Dictionary
Electronics Dictionary
ELECTRIC NETWORK
The electrical component (resistor, capacitor, inductor and supply sources) is connected in circuit in what ever manner i.e series or parallel is called electrical network.
COMPLEX NETWORK
It is those circuits which consist of many parameters (resistor, inductor etc) and these parameters are connected in such a manners
MAXIMUM POWER TRANSFER THEOREM
MAXIMUM POWER TRANSFER THEOREM
Maximum power transfer theorem may be stated as fallow.
A resistive load will abstract maximum power from a network when the load resistance is equal to resistance of the network as viewed from the output
THEVENIN TREOREM
THEVENIN THEOREM
Thevenin's theorem is a procedure by which we change a complex network in to simple network called thevenin's equivalent circuit.
Thevenin’s equivalent circuit of an open circuit voltage, thevenin voltage, Vth and the total resistance from the open terminals side, thevenin's equivalent resistance, Rth. Connected both thevenin's quantities in series. In this way we can find the current or voltage of any branch of the circuit.
STEP#1
Remove that resistance in
TRANSFORMER TYPES
TRANSFORMER TYPES
There are basically two transformer types .
- Step Down Transformer
- Step Up Transformer
Step Down Transformer
Step down transformers are used to step down high voltages i.e from 11000v to 220v or 110v and from 220v or 110v to 10, 12, 20 or 24 volts etc.
Because the same magnetic flux lines cut both coils of a transformer, the induced EMF in the secondary winding, is proportional
TRANSFORMER RESISTANCE TEST
TRANSFORMER RESISTANCE TEST
Resistance Test on a Transformer Connect an ohmmeter across the two ends of the primary winding of the transformer and record the resistance. See Figure.
Connect an ohmmeter across the two ends
EFFECT OF TEMPERATURE ON RESISTANCE
Effect of Temperature on Resistance
As we know that the resistance of the conductor are changes with change in temperature. So at the different temperature the resistance of the same conductor will be different.
METALLIC CONDUCTOR
The resistance increases as the temperature of a metallic conductor increase, so the resistance is directly proportional to the temperature. When
Transistor codes
Transistor codes
There are three main series of transistor codes used in the UK:
- Codes beginning with B (or A), for example BC108, BC478
The first letter B is for silicon, A is for germanium (rarely used now). The second letter indicates the type; for example C means low power audio frequency; D means high power audio frequency; F means low power high
DC/AC Converters – Inverters
DC/AC Converters – Inverters
Inverting
DC/AC converters named inverters are employed to convert a dc supply to an ac level of a definite frequency and value. Controlled semiconductor devices, such as transistors, SCR, and GTO thyristors are used in inverters. The input dc voltage may come from the
CATHOD RAY TUBE (CRT)
Cathod Ray Tube (CRT)
A CRT is an electronic tube designed to display electrical data.
The basic CRT consists of four major components.
- Electron Gun
- Focussing & Accelerating Anodes
BJT Bipolar Junction Transistor
BJT Bipolar Junction Transistor
This name is a representation for a device having transfer resistors. As we have seen a semiconductor offers less resistance to flow of current in one direction and high resistance in another direction, we call the device made of semiconductors as a transistor.
There are basically two types of transistors:
- Point contact
- Junction transistor
AC/AC Converters – Changers
AC/AC Converters – Changers
A switching converter that changes an ac supply to the ac supply with a different voltage, frequency, phase, or shape is called an AC/AC converter or changer. The first group of such converters unifies the direct frequency converters that change the frequency and ac voltage shape. Another group joins the dc link frequency converters
A.M Modulators
A.M Modulators
AM Modulator is one which is used for superimposing a low frequency signal on a high frequency carrier signal. In this modulator the amplitude of a carrier is varied in accordance with instantaneous value of message signal.
Types of A.M Modulators are listed
OHM LAW
OHM LAW
Ohm's law states that in an electric circuit the current is directly proportional to the applied voltage and inversely proportional to the resistance of the circuit. Provide the physical condition remain constant. This statement can be written in mathematical form as,
ATOM
ATOM
The smallest partial of the element, which remain the properties of the element.
OR
Atom is a Greek word and its means is particle, so atom is smallest particle of the mater, which has properties of element. E.g. Iron, Al, cu, etc
ATOMIC STRUCTURE
An atom is the smallest particle of an element that retains the characteristics of that element. According to the classical Bohr model,
Resistor
Resistor
Opposition to the flow of current is called resistance and the device or component used for this purpose is called resistor.
Example: 
Circuit symbol: 
Circuit symbol: Function
Resistors restrict the flow of electric current, for example a resistor is placed in series with a light-emitting diode (LED) to limit the current passing through the LED.
Connecting and soldering
Resistors may be connected
Simple UPS
Simple UPS
This is the circuit diagram of a simple UPS that can deliver 12V unregulated and 5V regulated DC. The transformer T1 steps down the mains voltage to 12V AC and then the bridge B1 rectifies it. The rectified signal is smoothed by the capacitor C1.When the mains supply is available the battery will be charged via diode D3 and the regulator IC gets supply via diode D5. 12V and 5V DC will be available at
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