ii 
 Safety Cautions  
 
 
 
Cautions for High Voltage 
 
High voltages, ranging from several hundreds to tens of thousands of volts, are used in electronic 
apparatus, such as radio and radar instruments. These voltages are totally harmless in most 
operations. However, touching a component inside the unit is very dangerous. (Any person other 
than authorized service engineers should not maintain, inspect, or adjust the unit.)   
High voltages on the order of tens of thousand volts are most likely to cause instant deaths from 
electrical shocks. At times, even voltages on the order of several hundred volts could lead to 
electrocution. To defend against electrical shock hazards, don't put your hand into the inside of 
apparatus. When you put in a hand unavoidably in case of urgent, it is strongly suggested to turn 
off the power switch and allow the capacitors, etc. to discharge with a wire having its one end 
positively grounded to remove residual charges. Before you put your hand into the inside of 
apparatus, make sure that internal parts are no longer charged. Extra protection is ensured by 
wearing dry cotton gloves at this time. Another important precaution to observe is to keep one 
hand in your pocket at a time, instead of using both hands at the same time.   
It is also important to select a secure footing to work on, as the secondary effects of electrical 
shock hazards can be more serious. In the event of electrical shocks, disinfect the burnt site 
completely and obtain medical care immediately.   
 
Precautions for Rescue of Victim 
of Electric Shock 
 
When a victim of electric shock is found, turn off the power source and ground the circuit 
immediately. If this is impossible, move the victim away from the unit as quick as possible without 
touching him or her with bare hands. He or she can safely be moved if an insulating material 
such as dry wood plate or cloth is used.   
Breathing may stop if current flows through the respiration center of brain due to electric shock. If 
the electric shock is not large, breathing can be restored by artificial respiration. A victim of 
electric shock looks pale and his or her pulse may become very weak or stop, resulting in 
unconsciousness and rigidity at worst. It is necessary to perform first aid immediately.