Feb 202020
 
Power Failure alarm using transformer and relay

Power failure alarm using transformer and relay

This power failure alarm circuit is very simple and is very useful when used with electric ovens, a refrigeration systems or to prevent a thief from cutting off the electrical power because it immediately warns of the problem. It also serves you when the fuses have blown.

  •  
    128
    Shares
  • 128
  •  
  •  
  •  
  •  
  •  
  •  
  •  
Feb 072020
 
Truth Table

What is a Truth Table?

The Truth Table is used to simplify boolean equations obtained from digital circuits. The truth tables can have many columns, but all tables operate in the same way.

Feb 062020
 
Light sensitive alarm using LDR

This light sensitive alarm is very simple and works using, as main components, a transistor, an LDR and a relay.

The alarm activates when the illumination level changes from almost total darkness to a moderately high illumination level. When this happens the alarm is locked and the alarm signal, be it a light or a sound, remains active.