My First Pulse Width Modulator Mod
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Looking good...
Ive been awol because my ISP is down. I'm actually in my truck now picking up wireless from 9.5 miles away. Slow but working =].
Ive been awol because my ISP is down. I'm actually in my truck now picking up wireless from 9.5 miles away. Slow but working =].
I had a problem last night , thunderstorm rolled threw took out the power for a few hours. By the time it came back on i had enough beer in me to know better then to drink and CAD.
Getting close to flipping the board and doing the other side. Other side will be easy, it is mainly my board thats holding me up. I believe i got everything worked out so i hope to be etching in about a hour or two.
Missed a trace off of pin two in the above image two posts back. Got that fixed. Might want to double check the circuit make sure nothing else is messed up
Getting close to flipping the board and doing the other side. Other side will be easy, it is mainly my board thats holding me up. I believe i got everything worked out so i hope to be etching in about a hour or two.
Missed a trace off of pin two in the above image two posts back. Got that fixed. Might want to double check the circuit make sure nothing else is messed up
i wont be able to check it over till later, driving into work to fix an outage
If anyone is going to use this circuit with unprotected batteries and needs a little zener diode safety margin to keep from overdischarging, here is what I came up with on the breadboard last night:
The zener between pin 1 and ground shuts the ground to the 555 off if the battery goes below the zener voltage (I believe I used a 6.3v, whatever the common size is in the 6v range). I only got to test it above 7.4v and below 5v, i didn't have a close to dead battery to find exactly where it shuts down though. Once I get a battery down into the 6v range I will test it more thouroughly.
Good work on the mini SMD board btw bstedh and Java_Az. Can't wait to see the final product up and running.
The zener between pin 1 and ground shuts the ground to the 555 off if the battery goes below the zener voltage (I believe I used a 6.3v, whatever the common size is in the 6v range). I only got to test it above 7.4v and below 5v, i didn't have a close to dead battery to find exactly where it shuts down though. Once I get a battery down into the 6v range I will test it more thouroughly.
Good work on the mini SMD board btw bstedh and Java_Az. Can't wait to see the final product up and running.
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Ok delayed once again. The layout for my board had a problem. It wouldnt have worked out so well if i couldnt get the atomizer power wire soldered in. I believe I finally have a solution worked out that doesnt require me making the board bigger actually might be able to shave another .100' of a inch off it . So might still get this thing etched tonight. I all else fails i will just do the PWM by itself tomorrow if it comes down to it. although i would for sure rather kill two boards with one stone.
Edit: Here is both sides of what i got. Moving the pot towards the middle cut me off from half the switch. I really dont think it will matter though. Let me know what you think. If your good with the switch side the way it is i will fill in as much ground as i can, It will help with heat as it acts like a heat sink.
keep in mind the switch side is not getting mirrored. I will print it out on the photo paper as it is. when transferred to the board it will in effect get mirrored. So think about it now like your inside the board or looking threw a invisible board from the other side. It really doesnt effect anything on the switch side accept the Zener. If you look at the data sheet it will look wrong but it is correct due to the transfer mirror effect.
OPTIONAL PARTS
350-2055-1-ND LED INGAN BLUE CLEAR 1206 SMD --------Optional LED light BLUE
P220KECT-ND RES 220K OHM .25W 5% 0603 SMD ___---Resistor calculated for BLUE LED @ a nominal voltage of 7.4 volts.
REVISED PARTS LIST
1 10 RNCP0603FTD150RCT-ND RES 150 OHM 1% 0603 SMD
2 10 RHM220DCT-ND RES 220 OHM 1/5W 5% 0603 SMD
3 10 296-16792-ND IC OSC MONO TIMING 500KHZ 8-SOIC
4 10 3352W-501LF-ND POT 500 OHM THUMBWHEEL CERM ST
5 10 641-1283-1-ND DIODE SCHOTTKY 100MA 30V 0603
6 10 445-5099-1-ND CAP CER 10000PF 25V X7R 0603
7 10NCNR DMN2020LSN-7DIDKR-ND MOSFET N-CH 20V 6.9A SC59
8 10 P12301SCT-ND SWITCH LT 4.7MMX3.5MM 350GF SMD
9 10 BZX84C6V2WDICT-ND DIODE ZENER 6.2V 200MW SC70-3
Edit: Here is both sides of what i got. Moving the pot towards the middle cut me off from half the switch. I really dont think it will matter though. Let me know what you think. If your good with the switch side the way it is i will fill in as much ground as i can, It will help with heat as it acts like a heat sink.
keep in mind the switch side is not getting mirrored. I will print it out on the photo paper as it is. when transferred to the board it will in effect get mirrored. So think about it now like your inside the board or looking threw a invisible board from the other side. It really doesnt effect anything on the switch side accept the Zener. If you look at the data sheet it will look wrong but it is correct due to the transfer mirror effect.
OPTIONAL PARTS
350-2055-1-ND LED INGAN BLUE CLEAR 1206 SMD --------Optional LED light BLUE
P220KECT-ND RES 220K OHM .25W 5% 0603 SMD ___---Resistor calculated for BLUE LED @ a nominal voltage of 7.4 volts.
REVISED PARTS LIST
1 10 RNCP0603FTD150RCT-ND RES 150 OHM 1% 0603 SMD
2 10 RHM220DCT-ND RES 220 OHM 1/5W 5% 0603 SMD
3 10 296-16792-ND IC OSC MONO TIMING 500KHZ 8-SOIC
4 10 3352W-501LF-ND POT 500 OHM THUMBWHEEL CERM ST
5 10 641-1283-1-ND DIODE SCHOTTKY 100MA 30V 0603
6 10 445-5099-1-ND CAP CER 10000PF 25V X7R 0603
7 10NCNR DMN2020LSN-7DIDKR-ND MOSFET N-CH 20V 6.9A SC59
8 10 P12301SCT-ND SWITCH LT 4.7MMX3.5MM 350GF SMD
9 10 BZX84C6V2WDICT-ND DIODE ZENER 6.2V 200MW SC70-3
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If anyone is going to use this circuit with unprotected batteries and needs a little zener diode safety margin to keep from overdischarging, here is what I came up with on the breadboard last night:
The zener between pin 8 and ground shuts the ground to the 555 off if the battery goes below the zener voltage (I believe I used a 6.3v, whatever the common size is in the 6v range). I only got to test it above 7.4v and below 5v, i didn't have a close to dead battery to find exactly where it shuts down though. Once I get a battery down into the 6v range I will test it more thouroughly.
Good work on the mini SMD board btw bstedh and Java_Az. Can't wait to see the final product up and running.
You confuse me... =] Pin 8 or pin 1? We have the Zener on Pin 8 on our board. I guess either way should probably work. What do you think.
I don't see any problem with the switch. If you want to fill in space you can etch the positive input along all the edges of the switch side as that will be pinched against the body which will be positively polarized.
That's a bummer about your board. I hope working on this isn't the cause.
Would you like me to send you back a completed board or are you going to put your own together?
That's a bummer about your board. I hope working on this isn't the cause.
Would you like me to send you back a completed board or are you going to put your own together?
Has anybody done a POT resistance vs output RMS V on this circuit yet? If not what range of POT's should I purchase to experiment with voltage levels? I'm not sure if my MM has RMS. It's the most expensive one Harbor freight had but is still a cheap meter even though it has capacitance and semiconductor ranges.
No this has nothing to do with it. It is this things fault.
After taking a closer look the inducter would have been point oposite of the way i thought it was. Might not think it would make a difference but space i had planned for is really tight prevents me from getting a needed wire in a .032 hole. But good news is i believe i have a better way to do it now. I think i can even get a Ti module to work also and have room for the big fat electrolytic caps.
I can get a trace to the other side of the switch if i fill positively. I was wondering how you planned on doing that, good to know. Although i think i should do as much negative around the Neg input. That is right next to the Mosfet and the mosfet is going to be the hottest running part for sure.
Just need to double check that zener not sure if i have it right or not now. Should it be pointing towards the switch or the input ???
I dont have a rms. I did a duty cycle on it and also a amp test. It will go from full amps to Zero with the 10k pot and a duty cycle from 100% to 10%. I will throw my 250ohm back on the breadboard and see what i get. post some results in a bit
That's funny because that exact part is what put me in the direction of this PWM. I wanted to use that but couldn't fit it and a thumbweel pot into the switch housing. Plus the inductor would interfere with the positive atty connection.No this has nothing to do with it. It is this things fault.
After taking a closer look the inducter would have been point oposite of the way i thought it was. Might not think it would make a difference but space i had planned for is really tight prevents me from getting a needed wire in a .032 hole. But good news is i believe i have a better way to do it now. I think i can even get a Ti module to work also and have room for the big fat electrolytic caps.
I can get a trace to the other side of the switch if i fill positively. I was wondering how you planned on doing that, good to know. Although i think i should do as much negative around the Neg input. That is right next to the Mosfet and the mosfet is going to be the hottest running part for sure.
Just need to double check that zener not sure if i have it right or not now. Should it be pointing towards the switch or the input ???
THis was my original layout idea
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I think you may have the wrong leg of the zener tied to the switch. You can connect both legs of the one side together as one leg is unused.
http://www.diodes.com/datasheets/ds30066.pdf
As far as which way it faces I can't remember the conduction direction of the zener =[ If you make pads on both sides identical long pads it can be soldered in either way.
http://www.diodes.com/datasheets/ds30066.pdf
As far as which way it faces I can't remember the conduction direction of the zener =[ If you make pads on both sides identical long pads it can be soldered in either way.
I may just use a small piece of spring wire to push against the body to make the positive connection to avoid the high heat required to solder the connection.
here is the chip side. Not sure what you want to do about the power carring neg output. It is close to the edge and fat but it really need to be on the big side for the amps that are going to be going threw it. I guess i could cut it down a bit and get a small positive boarder going up there. What you think ?
here is the chip side. Not sure what you want to do about the power carring neg output. It is close to the edge and fat but it really need to be on the big side for the amps that are going to be going threw it. I guess i could cut it down a bit and get a small positive boarder going up there. What you think ?
No need to worry about the short sides. They will not be making contact with the body... also the edges of this side will be facing down on the support so no worries on this side...
As far as I can tell the board matches the schematic wit the zener, led, and clamping resistor modifications. I think you are good to go. I am going to go eat now also... then shower and off to trouble shoot a microwave radio link...
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