Relay shut down circuit needed please...................
Relay shut down circuit needed please...................
(OP)
I am asking for help to design a circuit that will remove/interrupt ground on coil of standard bosh type relay (terminal #86) when monitored circuit voltage exceeds 15.5 volts.
Thank you for your help.
Thank you for your help.





RE: Relay shut down circuit needed please...................
What is going to be switched (do we have to worry about transients), what's doing the switching (does it have enough power), how many are going to be produced (whats the cost factor), etc.
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Relay shut down circuit needed please...................
Not concerned with transits/spikes.
The relay coil I want to interrupt pulls less than an amp (around 400 mA).
Would like the "CIRCUIT" to remove/interrupt ground on coil if vehicle voltage exceeds 15.5 amps.
This relay is the standard Bosch type relay.
Hope this helps.
Thanks.
RE: Relay shut down circuit needed please...................
Dan - Owner

http://www.Hi-TecDesigns.com
RE: Relay shut down circuit needed please...................
The requested "CIRCUIT" is controlling the Bosch relay.
The requested "CIRCUIT" will be powered by vehicle system voltage (14 - 15 volts).
Only want to build 2 or 3 of these.
Thank for your help.
RE: Relay shut down circuit needed please...................
RE: Relay shut down circuit needed please...................
I'll give it a shot!!!!!
RE: Relay shut down circuit needed please...................
You need a circuit that switches on a certain voltage. Look to using a battery monitor IC driving a transistor. Battery monitor IC's are the type of thing put into a device to ensure the battery does not get overly discharged. Just invert the logic.
RE: Relay shut down circuit needed please...................
The auxiliary relay coil will protect the zener from transients.
What worries me is that the OP probably wants to keep a load dump from hitting some equipment. A relay that makes another relay drop out will probably not be fast enough. But since the OP is not willing to reveal more "secrets", we will have to do with this not so well specified or designed "circuit".
Gunnar Englund
www.gke.org
--------------------------------------
100 % recycled posting: Electrons, ideas, finger-tips have been used over and over again...
RE: Relay shut down circuit needed please...................
RE: Relay shut down circuit needed please...................
You may have a comparator w/some hysteresis to drive the 2d N/C relay, already suggested for breaking the coil's GND path. Also a TL431 as ref. input for the opamp.