Do u know about the electric shock?

ANS:
From 0 to 0.5 mA - no sensation
1 mA - threshold of perception
From 1 to 3mA - weak sensation
From 3 to 10 mA - painful sensation
10 mA - threshold of muscular
contraction in the arms
30 mA - threshold of respiratory
paralysis
75 mA to 100 mA - threshold of cardiac
fibrillation (probability 0.5%)
250 mA - cardiac fibrillation with
99.5% probability (for an exposure
time of 5 seconds)
4A - threshold of cardiac paralysis
(sudden stoppage of the heart)
5A - burning of organic tissues
The magnitude of the applied voltage
necessary to produce dangerous
current values depends on the
resistance of the body, where body
resistance varies between wide limits.
Between hand and foot, for example,
assuming good electrical contact, the
resistance is about 500 Ohms ,
excluding skin resistance. The skin
resistance varies from about 1000
Ohms /cm^2 for wet skin to about 3 x
10^5 Ohms /cm^2 for dry skin.
Now think what will happen to your tissues
 

Define the following: Average demand, Maximum demand, Demand factor, Load factor.

ANS:
 
• Average Demand: the average power requirement during some specified period of time of considerable duration is called the average demand of installation.

• Maximum Demand: The maximum demand of an installation is defined as the greatest of all the demand, which have occurred during a given period. It is measured accordingly to specifications, over a prescribed time interval during a certain period.

• Demand Factor: It is defined as the ratio of actual maximum demand made by the load to the rating of the connected load.

• Load Factor: It is defined as the ratio of the average power to the maximum demand.

mosfet capacitor configuration images

555 Timer PWM Audio Amplifier

Ans:

In its most simplistic form an amplifier can be built with a single 555 timer. In this project, a 200mA of current capability is enough to drive a small speaker, which makes it a good replacement for a low power amplifier. But when more power is needed to allow listening music in a small room then a high power stage needs to be added with it.

The function of 555 timer is very much comparable to pulse width modulation (PWM). The value of the component used in the circuit causes 555 to oscillate at approximately 66 KHz. As we know, speaker does not respond to this much high frequency. Instead it responses to the usual CD value of the modulated output and explains the concept of PWM.