Power Supply Failure Indicator Circuit

Power Supply Failure Indicator


Power Supply Failure Indicator Circuit

Many circuits, especially digital systems such as random access memories and digital clocks, must have a continuous power supply to ensure correct operation. If the supply to a RAM is interrupted then the stored information is lost, as is the time in the case of a digital clock.

The supply failure indicator described here will sense the interruption of the power supply and will light a LED when the supply is restored, thus informing the microprocessor user that the information stored in RAM is garbage and must be re-entered, and telling the digital clock owner that  his clock must be reset to the correct time.

Power Supply Failure Indicator Circuit

PARTS LIST
R1 100kΩ
R2 10kΩ
R3 10kΩ
R4 680Ω
C1 10nF (103)
D1 LED
D2 1N4148
IC1 741
PB1 Push Button Switch

When the supply is initially switched on the inverting input of IC1 is held at 0.6V below positive supply by D2. Pressing the reset button takes the non-inverting input of IC1 to positive supply potential, so the output of IC1 swings high, holding the non-inverting input high even when the reset button is released. LED D1 is therefore not lit.

When the supply is interrupted all voltages, of course, fall to zero. Upon restoration of the supply the inverting input of IC1 is immediately pulled up to its previous potential via D2. However C1 is uncharged and holds the non-inverting input low, so the output of IC1 remains low and D1 lights.

Power Supply Failure Indicator Power Supply off Failure error Indicator Circuit


Please send your ideas, which are very important for our success…

About

Ravindra, Hi...


Tags: ,
3 comments on “Power Supply Failure Indicator Circuit
  1. amit says:

    after inttrruting the supply for how much time the led will glow IN POWER FALIOR INDICATOR

  2. amit says:

    thanks sir , this is very helpful for me .
    sir, i request u that tell us brefily explanations component used in this ckt. so that we can teach much better.
    thanks again my dear sir.

  3. ashish says:

    after inttrruting the supply for how much time the led will glow.

Leave a Reply

Your email address will not be published. Required fields are marked *

*


You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

Enter your email address:

LINKS
Share/Bookmark
Electronics