CHONDA INTERNATIONAL TECHNOLOGY CO.,LTD

Favorite  |  Set Home
News
 


Shield



In order to effectively suppress the EMI emitted by the radiated electromagnetic energy inside and outside the device through the space, the usual solution is shielding. Specific electric field has three types: Electronic shield,Magnetic Shield,and Electromagnetic field.
 CHONDA POWER test proving that: It is a good idea to shield for instruments and equipment with a computer system, which effective influence on electromagnetic interference and static electricity interference. Different shielding methods and materials have different effects.
 

1# Electric field shielding
 

The mutual induction of potentials between different objects in an instrument can be consider as the voltage distribution between distributed capacitances. In order to reduce the interference of the interference source to the induced object, the usual solutions are: Increase the distance between the interference source and the object to be sensed and reduce the distributed capacitance.

Place the sensor object close to the ground plate as much as possible to increase the capacitance to ground. Add a metal shielding layer between them. The shield must be a well-conducting conductor, and it must have adequate strength and grounding.

For example, an electrocardiograph, a monitor, an acupuncture electrotherapy device, or a silver needle that directly contact 
the human body,it is important to keep away from the radiation area of ultra-short wave therapy machines, high-frequency electric tools, X-ray machines, CT, MRI, and all medical equipment that can radiate electromagnetic waves.
 

2# Magnetic Shield
 

Magnetic shielding refers to the DC shielding or low frequency magnetic fields. The shielding principle is to use the high magnetic permeability and low magnetic resistance of the shield, to act as a magnetic shunt on the magnetic flux.to reduce the inside magnetic field. In order to reduce the magnetic resistance of the shield, the material used must be a material with a high magnetic permeability and a certain thickness. 
 
Shielded have to put at the center of the body, pay attention to the gap. Ventilation holes etc should be distributed along the direction of the magnetic field. Electromagnetic shielding is one of the major measures of electromagnetic compatibility technology.

That is, using a metal shield material will electromagnetic a means of closing the source of the interference so that the external electromagnetic field strength is lower than the allowable value; or using a metal shielding material to close the electromagnetic sensitive circuit, to make its internal electromagnetic field strong.
 

3# Electromagnetic field shielding


The circuit includes an inverting device coupled to a winding in the secondary winding, for generating a phase opposite to the phase of a voltage signal, induced from the secondary winding to the anode;

An oscillating means for oscillating a voltage signal output, from an output node of the inverting means, and causing the oscillated signal to be level-matched with the high voltage; and an electromagnetic field.

Generating means for applying a voltage signal output from an output node of said oscillating means to generate an electromagnetic field responsive to substantially surrounding the front of said kinescope.

The voltage signal and eliminates and shields the electromagnetic field generated from the anode. As a result, the circuit can be applied to a variety of sizes of cathode ray tubes at a lower cost,which can promote the production efficiency.