Hello everyone,
in my late 30`s electronics became my hobby... I`m an chem engineer by profession and want to combine it with electricity manipulation knowledge. I´m going to read and study...but I prefer to learn from examples. I have the following problem: constructing a climate control chamber for my experiments: T and rel.hum. control I can manage (comparator, transistors, 555, ...-not so hard to understand - simple on/off control) but I want this addition: I have 3, 3-pin 12V/DC fans, together drawing cca 0,9A (starting voltage ~7V). They are going to control access humidity via sensor (the one with linear voltage output, supply 4-5,8v/DC). In my desired range (45%-80%) voltage rises from 2,2 - 3,2V/DC respectively. System is going to be powered from 12V dc adapter (1,5A max). I want my analog circuit to do following: turn ON the fans at set values (for example 55%, 65%, 80%,....) on full rotation speed and with decreasing humidity gradually slowing them down to standstill - that is 5% rel.hum. bellow the set value (80-75%).
Can someone please advise me the smoothest way to accomplish that.
Thanks.
Matej
in my late 30`s electronics became my hobby... I`m an chem engineer by profession and want to combine it with electricity manipulation knowledge. I´m going to read and study...but I prefer to learn from examples. I have the following problem: constructing a climate control chamber for my experiments: T and rel.hum. control I can manage (comparator, transistors, 555, ...-not so hard to understand - simple on/off control) but I want this addition: I have 3, 3-pin 12V/DC fans, together drawing cca 0,9A (starting voltage ~7V). They are going to control access humidity via sensor (the one with linear voltage output, supply 4-5,8v/DC). In my desired range (45%-80%) voltage rises from 2,2 - 3,2V/DC respectively. System is going to be powered from 12V dc adapter (1,5A max). I want my analog circuit to do following: turn ON the fans at set values (for example 55%, 65%, 80%,....) on full rotation speed and with decreasing humidity gradually slowing them down to standstill - that is 5% rel.hum. bellow the set value (80-75%).
Can someone please advise me the smoothest way to accomplish that.
Thanks.
Matej