I HATE to ask what will seem an obvious, n00b, annoying question that has been asked in other ways before, but seems as simple as 1+1 to you guys. To me, however, its like speaking Chinese. I have zero formal education in electronics.
I would like to use the 555 timer PWM circuit (http://www.dprg.org/tutorials/2005-11a/index.html) for controlling a +12vdc solenoid valve. It has to be either a 25Hz or 31Hz frequency (to match other hardware controls), but I can't seem to get the frequency formula correct. How do I work it??
For that link, they give the formula as Frequency = 1.44 / (R1 * C1). When I plug in 1.44 / (100000 * .1), I get .000144; 1/.000144 is 6944Hz, or am I seeing that wrong?? Do electrical engineers have a different definition of frequency, or do I plug the farads in differently? I've seen absolutely no websites show the values in the formula, just the raw formula, frequency, and schematic. For me, "monkey see monkey do" is usually the way I learn.
Again, I apologize for such a base question. I just can't find an answer I understand, and I've searched for a while. Although all I need are the values to make 25Hz & 31Hz, I'd LOVE to see the working formulas showing numbers, not letters. I would like to use different component values since I have some scrap pots & caps I could save money with.
PS: An IRF510 would work in place of the IRFZ46N, right? My solenoid draws 5.4 watts, and radioshack shows it capible of dissipating 20 watts.
I would like to use the 555 timer PWM circuit (http://www.dprg.org/tutorials/2005-11a/index.html) for controlling a +12vdc solenoid valve. It has to be either a 25Hz or 31Hz frequency (to match other hardware controls), but I can't seem to get the frequency formula correct. How do I work it??
For that link, they give the formula as Frequency = 1.44 / (R1 * C1). When I plug in 1.44 / (100000 * .1), I get .000144; 1/.000144 is 6944Hz, or am I seeing that wrong?? Do electrical engineers have a different definition of frequency, or do I plug the farads in differently? I've seen absolutely no websites show the values in the formula, just the raw formula, frequency, and schematic. For me, "monkey see monkey do" is usually the way I learn.
Again, I apologize for such a base question. I just can't find an answer I understand, and I've searched for a while. Although all I need are the values to make 25Hz & 31Hz, I'd LOVE to see the working formulas showing numbers, not letters. I would like to use different component values since I have some scrap pots & caps I could save money with.
PS: An IRF510 would work in place of the IRFZ46N, right? My solenoid draws 5.4 watts, and radioshack shows it capible of dissipating 20 watts.