Theæ definition of farad is as follows; SI unit of capacitance, formally defined to be the capacitance of a capacitor between the plates of whichæthere appears a potential difference of one volt when it is charged by a quantity of electricity equal to one coulomb.
When does a capacitor act as a resistor of infinite resistance?
When the frequency is zero(i.e when dc power is supplied), capacitor is open is treated as open circuit having infinite resistance.
What component develops the output signal in a common emitter amplifier?
The voltage drop across the emitter-collector junction develops the output signal with the help of a resistor or two in series. The output is 'seen' at the collector.
How do you interpret the four colour bands in resistor?
First You need to identify four colors after that each color has some certain value
look up the table-
Black- 0
Brown- 1
Red- 2
Orange- 3
Yellow- 4
Green- 5
Blue- 6
Violet- 7
Gray- 8
White- 9
Golden-5%
silver-10%
no color-20%
DETECTING VALUES FROM COLOR CODE
mark the value of first color after THAN mark the value of second color(marking from left to right) and after that third color has value power of 10, and after that mark the tolerance value
for example --
let the color of resistance is
BROWN-BLACK-ORANGE-GOLDEN
VALUE OF BROWN IS - 1
VALUE OF BLACK IS- 0
VALUE OF ORANGE IS- 10 to the power 3 (1000),BCoz orange has value-3
VALUE OF GOLDEN IS - 5% (IT IS TOLERANCE OF RESISTANCE)
SO THE FINAL VALUE BECOME 10000 OHM +- 5%
Why you are calculating average and rms values for ac supply?
We will always calculate rms value only since the average value of ac current or voltage is zero. So we are using rms values in the ac circuit to calculate the power and to solve an ac circuit.
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Why rectifier is not used in dynamo?
rectifier is not used because of damaged of problem
Answer.
Because there's no need for that since the lamp on your bicycle can still work on the induced AC power.
What will happen current transformer connected in parallel?
If current transformers are connected in parallel, they will superpose and supply a high current.
EDIT:
I suppose you drive the transformer with a voltage source.
By the way, it depends how you connect the transformers:
A - primary side in parallel and two independent loads at the output
B - primary sides in parallel and secondary sides in parallel
Say turns ratio is Np:Ns, then for each transformer you have
Vp/Np=Vs/Ns, Np*Ip=Ns*Is.
IE If Np=N, Ns=1, you have a voltage step down transformer
(Vs=Vp/n, Is=N*Ip)
A: You will impose the same secondary voltage to each load, that is Vs=Vp/N.
Input current is the sum of each output load multiplied by transformer turns ratio. If the two transformers have M and N turns ratio, you have Iin = M Is1 + N Is2 (Is1=Is2 only if loads are identical)
This architecture is used in modular / redundant systems.
B: Theoretically, it's like having a single transformer. In practice, I have never seen it. What you do is to split the current in two different cores, so that your losses will be lower for each core. That *could be handy if you wanna use ferrites which are undersized for your application and you don't want to buy a new one.
How do you conduct test on speed control of DC motor using SCR?
Connect the SCR in series with the armature or field and control the firing angle of the SCR which in turns determine the current flowing to the armature or field.
How can avalanche breakdown be avoided in FET?
Breakdown depends on the electric field value in FETS (as in diodes and such, where you can find a junction).
Theoretically, you need to
- dope less the junction region of your device (like p-i-n diodes, the i (intrinsic) region is not doped in order to reduce E field peak, which occurs near the center of the device).
- raise the length of your device
Both of these two solutions will have the drawback of increasing your ON resistance.
At circuit design level, you can protect your devices with clamp diodes or something similar.
What happens when both emitter and collector are forward biased?
When base signal is given to transistor at the time of forward bais of emitter and collector the current flows from high potential to low potential
Clock is propagated from one T or JK flip flop to another hence it works.
A ripple counter works by the following principle. A clock pulse is applied to the first flip flop and the output of the first flip flop acts as the clock input to the second flip flop and the sequence continues in that order.
What is the voltage divider theorem?
it is aa linear circuit that produces the output voltage from the fraction of its input. It is also known as potential divider.
What are the disadvantages of moving coil instrument?
power must be gotten thru moving parts to the coil
slip rings, festoons, tinsel
Which flexible coupling is appropriate for which type of misalignment?
may be it is best for torsional misalignmnent
What are the basic requirements and characteristics of transducers?
What is zenor and zener diode?
Zenor diode is allow to flow current in forward direction and it can also allow current in reverse direction when the voltage is above the certain value.
What is the theory for code conversion of binary to gray?
You will have to have some computer skills to learn how to do this. You have to put in the right code in order to get it to work.
When a dead short occur what happens to circuit resistance?
The circuit resistance is likely to gradually drop and in such case it will cause the circuit to burn down.
When your ripple is a lot lower than the supply voltage, here is a rule of thumb:
for a single diode rectifier: U = I/(100*C) with I in ampere, C in uF
for example 1A supply, 1000 uF cap, gives Upp = 1/100e-3= 10 Volts.
Use 60 for 60 Hz line systems.
for a bridge diode retifier: U = I/(50*C) with I in ampere, C in uF
for example 1A supply, 1000 uF cap, gives Upp = 1/50e-3= 5 Volts peak to peak.
Use 120 for 60 Hz line systems.
Note: it is only an approximation, does not include resistances etc.
When does the armature of dc motor gets over heated?
a properly designed motor wont overheat unless it is overloaded
this is something like 3/4" drill with a 1/4" shaft that is used to drill in steel
sometimes hole saws have a 1/4" mandrel that will hold the entire line of saws
the motor must be matched to the load