building a custom circut, is it possible?

scampo77 · 3rd December 2009, 01:31 AM

im not sure if this is the right catagory or even the right forum but i have had a lot of luck from this community and a lot of helping ideas have been offered so i thought i should try here first.

i need a circuit that engages a relay at 4.7 DCV and then disengages the ralay at 5 DCV.

is this possible? is this difficult?

what it is for is for engaging cooling fans i have measured everywhere and this is the biggest range of voltage that i can find. any ideas or links would help me out a lot

Perry Babin · 3rd December 2009, 08:58 AM

If you want the fan to operate only when the voltage is between 4.7v and 5v, a window comparator would do it. It's not complex. It would require two op-amps resistors and a voltage reference (or regulator).

3rd December 2009, 01:31 AM	#1
scampo77 diyAudio Member Join Date: Jul 2008 Location: Montreal	building a custom circut, is it possible? im not sure if this is the right catagory or even the right forum but i have had a lot of luck from this community and a lot of helping ideas have been offered so i thought i should try here first. i need a circuit that engages a relay at 4.7 DCV and then disengages the ralay at 5 DCV. is this possible? is this difficult? what it is for is for engaging cooling fans i have measured everywhere and this is the biggest range of voltage that i can find. any ideas or links would help me out a lot

3rd December 2009, 08:58 AM	#2
Perry Babin diyAudio Member Join Date: Nov 2003 Location: Louisiana	If you want the fan to operate only when the voltage is between 4.7v and 5v, a window comparator would do it. It's not complex. It would require two op-amps resistors and a voltage reference (or regulator). __________________ Links >> Basic Car Audio Amp Repair --- Basic Car Audio Electronics --- Basic Transistor Testing --- Basic Switching Power Supply Design --- Basic Computer Skills << Links

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