THE LO-VO AMERICAN ELECTRICIANS HANDBOOK: A guide or how too, send induced electricity at a subjects precise body cavity, organ, or nerve receptor
AMERICAN ELECTRICIANS’ HANDBOOK 1942
THE ETHER SPECTRUM
Explanation of Light. Light ("Standard Handbook for Electrical Engineers") may be defined as radiant energy of those wave lengths to which the human eye is sensitive.
Figure 1 shows the complete
ether spectrum of electromagnetic waves, which travel through space at the velocity of approximately 186,000 miles per second. The longer waves are the ones used in radio communication; the shortest ones are the X rays and cosmic rays. The waves to which the eye is sensitive are those near the middle of the spectrum, of a length of about 0.0004 to 0.0008 mm.
TRANSDUCER
TRANSDUCER
ultrasonic transducer. A device that sends and receives the sound wave signal.
pulse-echo transducer. An ultrasonic transducer that sends out intermittent (pulsed) signals rather than continuous sound waves and receives the echo signal. Pulsed-wave Doppler ultrasound is used to measure blood flow and the depths from which echoes originate.
continuous wave transducer. An ultrasonic transducer that sends a constant and continuing signal that is not pulsed.
WAVEFORM OF ALTERNATING CURRENTS AND VOLTAGES
Wave Form of An alternating current or voltage is one which is reversed at regular intervals.
The curve formed by plotting the instantaneous values of the voltage or current against time is called the wave form of the voltage or current.
It is best to have the value of an alternating current or voltage vary with time according to what is known as the sine law. The instantaneous values of an alternating current vary according to this law. A voltage or current which varies in this manner is called a sinusoidal voltage or current. Most modern a-c generators produce a voltage which is very nearly sinusoidal and are generally so considered.
The current in some a-c circuits will be very nearly sinusoidal and in others may differ considerably from the sine law. In most cases, however, for practical work both alternating voltages and currents can be considered as following the sine law.