Dan Paulovich
- Jul 18, 2014
- 6
- Joined
- Jul 18, 2014
- Messages
- 6
I have an aneometer that puts out 0-2vdc. I want to monitor that voltage and trigger an alarm when the voltage gets below 1.5 vdc. Anybody have sugestions.
Thanks
Thanks
You end up making a very small circuit to generate a reference voltage.. and you feed that reference to one of the inputs on the comparator.Comparator.
Thanks
Adam
Do you have a circuit diagram with parts List?In other words, feed the aneometer output in to one of the comparators inputs. Then hook up a resistor voltage divider circuit that outputs 1.5V, and feed that into the comparators other input. The comparators output can be fed into a transistor, so you can switch on a alarm. See here for how to hook up the transistor to the comparators output.
If you have any questions about that, just ask.
Regards
Dan
Supply = 12 vdcI think I can draw you up one. what supply voltage to you want it to work off of? What voltage is the alarm? How much current does it draw?
Regards
Dan
Thanks Supercap2F I'll give it a try and let you know how it works out, I appreciate the help. I was an avid electronic experimenter back in the 60's, 70's and 80's but have not fooled around with it much since, will be fun to get back into it again.Here's what I was thinking:
View attachment 14159
Here's the parts list:
View attachment 14160
First of all, the little box that says 'U1' is just the power connections for the comparator. You will need to adjust the pot until the voltage at the + input of the comparator equals 1.5V (I'm assuming that you have a voltage meter). I did not include the resistors on the price list, because I do not know what wattage they should be. I think 1/4 watt would be good, but someone else needs to confirm that (maybe Gryd3 or Adam can tell us?).
Edit: Here is the 2N4401. Here is the comparator. Here is the 0.1uF capacitor.
Regards
Dan
(*steve*) said:Change your R2 (11R) and R1 (100R) resistor and pot to 10K and 100k and you'll waste a lot less power in the voltage divider.
Of course, this assumes that your 12V is regulated. If it's not regulated then your voltage reference will be all over the place.
I would also suggest placing a small capacitor (say 0.1µF to 1µF) across R2 to reduce noise.
Dan Paulovich said:I'll give it a try and let you know how it works out
Arouse1973 said:Good job by the way, glad you didn't get caught out by the old open collector drive scenario and you chose one with push pull output.
OK, good Idea Adam!Is this what you had in mind?
View attachment 14167
ThanksI looked through a ton of comparators to find that one.
Do you know what wattage resistors I should use?
All the best!
Dan