Forum: General Capacitor Questions & Issues
05-16-2022, 12:41 PM
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Replies: 356
Views: 472,893
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Forum: General Capacitor Questions & Issues
05-16-2022, 12:37 PM
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Replies: 9
Views: 302
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Forum: General Electronics Technical Discussion
05-13-2022, 12:28 PM
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Replies: 39
Views: 1,071
Re: TIP120 Question
Back in the late 70s and into the 80s, transistors were used rather than Darlingtons. At Boschert, we used 2N654# and MJE1300# transistors (TO-204 and TO-220, respectively) from Motorola. That was...
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Forum: General Electronics Technical Discussion
05-13-2022, 12:06 PM
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Replies: 39
Views: 1,071
Re: TIP120 Question
In addition to limiting the realistic maximum switch frequency, during those turn-on and turn-off times, the device is in its linear reason, i.e. dissipating power. As those turn-on and turn-off...
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Forum: General Electronics Technical Discussion
05-12-2022, 11:44 AM
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Replies: 39
Views: 1,071
Re: TIP120 Question
redwire is correct that I was confusing a C-B resistor with a Baker Clamp, which uses a diode to reduce storage time. Lo siento.
Basically, transistors' rise, fall, and storage time combine to...
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Forum: Troubleshooting Power Supplies and Power Supply Design
05-08-2022, 06:16 PM
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Replies: 12
Views: 349
Re: Power Man ip-p300bn7-2 blown
Putting together anecdotal comments I’ve seen around here, I wonder if a lot of the snap-in type caps, which were originally designed for 50/60 Hz usage, are not suitable for the high frequency...
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Forum: General Electronics Technical Discussion
05-06-2022, 11:40 AM
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Replies: 39
Views: 1,071
Re: TIP120 Question
I sit partially corrected about the TIP120 incorporating B-E resistors. However I think those are to prevent leakage or noise from turning on the Darlington. IIRC, it's a C-B resistor that keeps a...
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Forum: General Capacitor Questions & Issues
05-06-2022, 11:28 AM
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Replies: 9
Views: 302
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Forum: General Capacitor Questions & Issues
05-05-2022, 06:20 PM
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Replies: 9
Views: 302
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Forum: General Capacitor Questions & Issues
05-04-2022, 04:40 PM
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Replies: 9
Views: 302
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Forum: General Capacitor Questions & Issues
05-04-2022, 04:22 PM
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Replies: 18
Views: 365
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Forum: General Capacitor Questions & Issues
05-02-2022, 11:17 AM
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Replies: 18
Views: 365
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Forum: General Capacitor Questions & Issues
05-02-2022, 11:13 AM
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Replies: 18
Views: 365
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Forum: General Electronics Technical Discussion
05-01-2022, 06:00 PM
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Replies: 12
Views: 332
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Forum: General Capacitor Questions & Issues
05-01-2022, 05:48 PM
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Replies: 18
Views: 365
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Forum: General Electronics Technical Discussion
04-29-2022, 10:58 AM
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Replies: 12
Views: 332
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Forum: General Electronics Technical Discussion
04-29-2022, 10:42 AM
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Replies: 6
Views: 249
Re: Resistor value - color coding
Based on the chart below, I'm guessing .3 ohm, 250 ppm tempco.
https://www.neodensmt.com/Content/upload/2019233559/201906241320349978362.jpg
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Forum: General Electronics Technical Discussion
04-27-2022, 10:56 AM
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Replies: 39
Views: 1,071
Re: TIP120 Question
I suggest adding a resistor base-emitter to reduce sensitivity to leakage and noise. This is normal practice with regular transistors, and I would think the high beta of a Darlington would make doing...
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Forum: Troubleshooting Power Supplies and Power Supply Design
04-25-2022, 11:34 AM
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Replies: 3,194
Views: 1,039,681
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Forum: Troubleshooting Power Supplies and Power Supply Design
04-22-2022, 11:50 AM
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Replies: 3,194
Views: 1,039,681
Re: Power supply build quality pictorial. part 2
How often have I posted this: those heatsinks do look reasonably substantial. The main transformer looks reasonable as well. 820uF for the input lytics seems a bit marginal for 500W (more OK for...
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Forum: Troubleshooting Power Supplies and Power Supply Design
04-14-2022, 03:37 PM
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Replies: 70
Views: 1,900
Re: A question about PWM IC's
Start-up current comes from "VIN" (also, line voltage sense). After it has started, house-keeping power for the IC comes from "VDD".
It is a current mode regulator, so it needs the output voltage...
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Forum: General Electronics Technical Discussion
04-11-2022, 05:45 PM
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Replies: 12
Views: 546
Re: Need new part for microwave
It's a bimetal thermal switch. It should open up if what it's mounted on gets too hot. It should close again when what it's mounted on cools.
On eBay,...
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Forum: General Electronics Technical Discussion
04-05-2022, 11:59 AM
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Replies: 13
Views: 658
Re: Question about MOSFET as a switch and a cap?
Assuming an N-channel MOSFET, for it to turn on the Gate must be several volts more positive than the source. The meaning of "several volts" will depend on the threshold voltage of the MOSFET....
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Forum: Troubleshooting Power Supplies and Power Supply Design
04-03-2022, 10:00 AM
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Replies: 14
Views: 538
Re: Aerocool cylon 700watt Atx psu
I think it's a Tiny Switch type all-in-on regulator. The "missing" pin 7 is probably the spacing between pin 8, the output MOSFET Drain, and pin 6, the Source. Whether it's literally is a Tiny Switch...
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