but
the
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actualy if its unsmothed rectified ac then the miller cap wont work anyway. instead you cld try puting a source resistor so that the curent varies more slowly with respect to the changing gate voltage. i not read all the other replies yet maybe youve fixed it already tho ..
Colin =^.^=
Does a dryer motor have a starting capacitor? That's what I'd look for.
John
the idea of using the miller efect is that the gate voltage varies only very slightly from full on to full off, and the point at wich it does this can vary a lot, so any capacitor from gate to ground is going to have much more efect on turn on time than fade time.
a much smaller capacitor from gate to drain will not have much efect while the device is fully on or fully off so wil not impose much delay, but as soon as the the drain voltage rises the capacitor wil charge up and this charge curent wil rob the gate of its drive stoping it from rising as fast, thus the rise time of the drain voltage is limited to the suplied gate current. dv/dt = I/c.
sorry it seems u have problems with it, see my other posts too, this thread seems to be totaly screwed up on my news server for some reason, 100s of duplicates that all arive many days late, and all disconected.
Colin =^.^=
-- Dunno, but... 1. What are you using for Vdd? 2. Are you using 4538's or 74HC4538's? 3. You could be frying the 4538 because you don't have Schottky diodes across the the timing resistors (cathode to Vdd) and the solenoid is pulling the supply down, allowing the timing caps to dicharge through the chip's protection diodes (yes, the dreaded parasitic SCR's rear their ugly heads...) BTW, did you get the circuit I emailed you?
That doesn't sit well Terry..... the volume allowed for the primary winding is the most valuable real estate on the bobbin. Having primary windings that do nothing doesn't sound right.
Is that how they are marked, or could there be some combination of windings that allow those idlers to be used?
-- Tony Williams.
-- Why? if 1.2AH will fire the thing under worst case conditions, day in and day out, and you can be sure that the PV array will always keep it topped off, then you should be OK. Just put some diodes across the resistors. You might also think of replacing the lead-acid (SLA?) battery with NiCd or NiMH for the lower internal resistance under pulse load, but you should install the diodes in either case.
I need URL of any educational website that features
Going to job interview, and want to review stuff.
Hi, I am working on a logic board that uses resistor packs. I'd like to know what they are without having to desolder them out. One is 10A102G. I assume this is a 10 pin 1K bussed type, A standing for bussed. The other is 8B331G. I am thinking 8 pin 330R isolated type, B standing for isolated. I really need to know if I am right on bussed and isolated. Hope someone can help me. Maybe there is a place on the internet to tell me that but I have been unable to find any info. Thanks. Jay
These numbers indirectly tell you the internal resistance of the supply. It's the slope of the graph, of course. Use that to figure out the dissipation at various current levels for both of these windings, add them up, and decide how much you want the transformer to dissipate.
Or, just put a load on it and watch the temp. rise. I think one of the gurus beat me to this one, however.
Have Fun! Rich
42.5 4.5
----- 47.0, which is pretty flippin' close to 46.9. I'd say, put the two small ones in series, and that string in parallel with the other one.
Maybe for a first smoke test, put a, say, .1R resistor in series with each to see how well they current-share.
Have Fun! Rich
It _could_ be, but it could also be any number of other things. You haven't shown any component values here. Do you even have a meter? Is the mic known good? Have you double-checked all your connections?
We need much more to go on here.
Good Luck, Rich
I'm getting ready to order some capacitors in the range of 1pF to 1uF and see that both regular ceramic and monolithic ceramic capacitors are available in the same capacitance, voltage, temp coefficient, price range. What's the difference in a regular ceramic and monolithic ceramic capacitor? Why would you use one over the other? Thanks. ______________________________________________________________________
GRAVITY:
It's not just a good idea-IT'S THE LAW!
what kind of power converter would i need to connect 3 of these laser pointers to a 110 volt wall outlet?
-- 5khzgjf9e001@sneakemail.com
I've been testing the watering circuit i built:
It was working OK with an LED in place of the coil, and a 10 uF capacitor instead of the 1000 uF one. I've just finished building the MOSFET switch part of the system, which works OK by itself.
I just tried testing it with the coil and the 1000uF capacitor, and now the 4538 is not working right and getting very hot when I switch the power on. Switching it off and leaving it doesn't fix the problem. Could this be a case of SCR latchup failure? The only way I can see that this could be happening is if the fully charged 1000uF capacitor is discharging through the 4538's A1 and B2 inputs. Is this likely to be the problem?
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after switching off, i mean. the main symptom apart from overheating is the 393 can't pull down the A1 and B2 inputs of the 4538 any more - it goes down to 10.63V and no further. With the 4538 disconnected, it works fine, switching between 0V and +12V.
-- http://www.niftybits.ukfsn.org/ remove 'n-u-l-l' to email me. html mail or attachments will go in the spam bin unless notified with [html] or [attachment] in the subject line.
The input to an RS232 serial port is supposed to swing between +12V and -12V. A signal between +3 and -3 is undefined.
You can use a 1488 or one of the Maxim ICs to create the correct bipolar signal from your source.
You can also use a 4050 hex buffer for level shifting. Its inputs can withstand a 12 volt input when its supply is 5 volts. The output would then be capable of being read by the parallel port rather than the serial port.
See here:
What's that Lassie? You say that jaydee fell down the old sci.electronics.basics mine and will die if we don't mount a rescue by
10 Aug 2004 11:32:44 -0700:
This is true, but one will likely hog all the load unless they share one regulator. You may be able to wire the field coils in series and use one regulator. The alternators will have to be identical, and driven at the same speed.
Yes, you can. But the output will be three phase, and at a much higher frequency than household AC. And with more than one alternator, you will need separate transformers, due to the alternators not being in phase with each other.
You could make/buy a regulator that will let you get higher voltages from a standard auto alternator. And you can get inverters that will use that voltage to make AC. Last I saw, you could get large inverters that take in 48 VDC, and output 240AC.
You might want to find a booklet called "alternator secrets"
-- Dan
thinking about it, this is unlikely to be the problem - the capacitor would also be keeping the supply rails high while it discharged, so it wouldn't be driving the 4538 past the rails.
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a 12V 1.2Ah lead acid battery.
a 4538.
That could well be it - when the battery is low, the supply gets pulled down to around 7V. Maybe need a bigger battery.
Yes, thanks. It looks like it would work OK, but I'd rather stick with the design I have now.
-- http://www.niftybits.ukfsn.org/ remove 'n-u-l-l' to email me. html mail or attachments will go in the spam bin unless notified with [html] or [attachment] in the subject line.
Hi, I have a bunch of silver (colour), axial lead capacitors. They are about the size of a 1/4 - 1/2 W carbon resistor. I don't understand how to read the capacitor values from the markings on them, and webpages I've looked up don't help too much. I don't have a meter that reads capacitance, and I don't really want to make mistakes with the values. Hoping you can help me to understand how to read these. Here are some examples. Thank you in advance for any help you can offer. Keith creekchubbAThotmailDOTcom (replace AT with @, and DOT with .)
--example1--
39003 01-M 2283 +419A-------------
--example2--
39003 01-M 2267 J +524A-------------
--example3--
39003 01-M 2283 J +545A-------------
--example4-- M39003
01- 2408J 31433 +737 Y--(there is a crown mark between the 7 and the Y on this one-----------
--example5-- M39003
01-2 2362J 56289+ 8850F+----------
--example6-- C513B J683K
6508B +KJ-------------
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