links to cheap adjustable voltage triggers > switches

[user1235423643]

hello, can anyone recommend any cheap little circuits that can be setup to trigger at set voltages.

for example.  when i sees X voltage it will trigger a relay or transistor. and the unit can be adjusted with a pot. to X voltage.

even better is there is such a unit that does high and low settings. max and min.

(VSR voltage sensitive relays are on the market but cost over $50) retail stuff to $

thanks

[MosherIV]

I think this should work for you

http://www.zen22142.zen.co.uk/Circuits/Switching/schmitt.htm

[Seekonk]

The three terminal LM431 easily drives small relays.  Check application notes.

[Signal32]

Perhaps http://www.ebay.com/itm/-/222087837604

"enter a Voltage comparison with setting reference voltage, when the input voltage is greater than the reference voltage, the relay closed; when the input voltage is less than the reference voltage, the relay no action."
Doesn't sound like it would have min/max function, but you can use 2 to get min/max functionality.

Or this:
http://www.ebay.com/itm/-/162039421625
This one seems to be able to do min/max with only one unit

Did you want schematics or ready-made circuits?

[user1235423643]

yes something ready made prebuild

so it would be a Voltage Comparator ?

[mariush]

Lots of chips like what you want.

There's several sections at Digikey that have chips like what you want.

PMIC - Power Supply Controllers, Monitors  see , Specialized ( filter by Applications) : http://www.digikey.com/product-search/en/integrated-circuits-ics/pmic-power-supply-controllers-monitors/2556707
PMIC - Supervisors : http://www.digikey.com/product-search/en/integrated-circuits-ics/pmic-supervisors/2556197
PMIC Battery Management (see battery monitor or battery protection there ) :  http://www.digikey.com/product-search/en/integrated-circuits-ics/pmic-battery-management/2556336
PMIC - Power Management - Specialized : http://www.digikey.com/product-search/en/integrated-circuits-ics/pmic-power-management-specialized/2556708  filter by overvoltage protection
Specialized ICs (see overvoltage protection at type) : http://www.digikey.com/product-search/en/integrated-circuits-ics/specialized-ics/2556114

[user1235423643]

thanks. but digi key is no help.

any ebay links?