is 5-7 VDC enough to throw a Bosch relay

the power is pulsed. if so how would I wire the relay to cut power once this is sensed?

the relay doesn't draw voltage, it draws amp's, around 150 - 200mA. You probably have that, but check anyway. to get the relay to stay open (on the 87a terminal), you need to wire a capacitor across the coil, but the size depends on the duration of the pulses. if they are like a second or so apart, i would start with about a 4700uF cap and play with different sizes from there. Im not sure if it matters or not, but you might want a polarized cap, not a non-polarized. The cap will store the energy from the pulse and will discharge when there is no power, ie: between pulses. did that help?

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93 4RUnner
Alpine H/U
Alpine Mids/Highs
Alpine Security w/DEI remote
start and window control
Rockford Lows.

the one in front of me triggered at 5.2 volts, but that is kinda low and I wouldnt expect it to trigger that low all the time. Do you have a higher voltage source available? if so you could use a transistor or a small reed relay to trigger the larger one... if not you can use capacitors to double the voltage (probably not worth the time)

CHaseHeadrick wrote:

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the relay doesn't draw voltage, it draws amp's, around 150 - 200mA. You probably have that, but check anyway. to get the relay to stay open (on the 87a terminal), you need to wire a capacitor across the coil, but the size depends on the duration of the pulses. if they are like a second or so apart, i would start with about a 4700uF cap and play with different sizes from there. Im not sure if it matters or not, but you might want a polarized cap, not a non-polarized. The cap will store the energy from the pulse and will discharge when there is no power, ie: between pulses. did that help?

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yes this helps.  Also is there a smaller relay I can use in my application beside this big bosch relay.  Im just trying to deprive and supply power to a small device.

also I have thought about using a diode on the ground instead of a relay.  check this thread https://www.the12volt.com/installbay/forum_posts.asp?tid=33888&PN=1

Thanks

after reading your other post, i don't know if my idea will work. i assumed the pulse was continuous (like an LED pulse), not just three. im not sure how you would get the relay to stay open with three pulses, but you could use a latching relay and it would stay closed with just one pulse, then open with another pulse (or vice versa). Not sure about the smaller relays, i think there are some you can get at radio shack that are smaller physically, but i think they handle less power as well. what exactly are you wanting to do?

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93 4RUnner
Alpine H/U
Alpine Mids/Highs
Alpine Security w/DEI remote
start and window control
Rockford Lows.