how to check if volt is 14 or 18v ?

[janosandi]

Hello guys
i need a circuit to check the out volt of a receiver if its 14v or 18v

ur help will b appriciated

 

[ahmad1954]

you should use comparator and compare your voltage with 14 and 18 volt. there are many comparator in market.
you can use opamp as a simple comparator.

 

[janosandi]

thx would u plz guide me to simple circuit comparator ?

 

[ahmad1954]

see below links:
https://en.wikipedia.org/wiki/Comparator
https://www.dummies.com/how-to/content/electronics-components-how-to-use-an-op-amp-as-a-v.html
http://www.technologystudent.com/elec1/opamp3.htm

or you can use prepared comparator such as LA6393AM. if you search you can find many of them.

 

[Venkadesh_M]

Design a comparator with 16V as reference...

If you want easily means put a resistor divider with 6.8k and 2.2k put a low voltage comparator...


https://t3.gstatic.com/images?q=tbn:ANd9GcTBZC2rgHc87FQE2DJCgNPwYpm8yg1S_yaF9mkHwXP1T5FgC4vT

 

[BradtheRad]

If you want a visual indicator, and the source you are drawing from has sufficient current, then you can use a zener diode and two led's.

The first led lights at about 13V. The second lights at about 16 or 17 V.

Screenshot:

 

[janosandi]

thx guys i want to indicate both volts so when i have 13v i want a led & when 17v i want another one to insicate but the other goes off

 

[BradtheRad]

A transistor can serve to alternately switch between 2 led's.

Screenshot:



The single diode may need to be 2 or more diodes in a string, to prevent LED 1 from lighting dimly when it is supposed to be dark.