Search found 2488 matches

by mawyatt
Tue Mar 17, 2020 1:06 pm
Forum: Equipment Discussions
Topic: Vibration Test
Replies: 8
Views: 1237

Mike, I've been curious about the system implications of that "hot hair dryer" test. Or was that your point, that the whole system is subject to flexure except for the parts under closed loop control? --Rik Rik, Forgot to answer this. Yes, the parts under closed loop control don't have the same eff...
by mawyatt
Tue Mar 17, 2020 12:38 pm
Forum: Equipment Discussions
Topic: Vibration Test
Replies: 8
Views: 1237

Rik, My setup is probably typical of most and not specifically designed for thermal management. When I ran the crude test and it was just to see the thermal effects on the Piezo Stage under Closed Loop control, then just decided to compare against the focus rail. I wanted to see how the closed loop ...
by mawyatt
Tue Mar 17, 2020 9:07 am
Forum: Equipment Discussions
Topic: Vibration Test
Replies: 8
Views: 1237

Ray, What you might be experiencing is actually a thermal drift due to the air flow. A quick "hot hair dryer" test can revel just how sensitive these focus rail setups are to slight temperature transients. Originally, we did this "hot hair dryer" test to check the closed loop piezo stages and then j...
by mawyatt
Tue Mar 17, 2020 7:56 am
Forum: Equipment Discussions
Topic: Vibration Test
Replies: 8
Views: 1237

Jin, To add to what Chris mentioned, some stepper controllers introduce a sudden motor/stage "jerk" with motor starting and stopping. I recall (don't have a Stackshot now) your Stackshot has a parameter that allows acceleration and deceleration control, this was under the Stackshot control from Zere...
by mawyatt
Mon Mar 16, 2020 9:23 am
Forum: Photography Through the Microscope
Topic: EPROM
Replies: 8
Views: 1131

Chips are fascinating devices indeed!! This one JW has nicely imaged is an UV erasable EPROM (Erasable Programable Read Only Memory), where intense UV light can erase the entire chip memory. The "hole" in the package has a glass window for passing the UV light. Later these were replaced by electroni...
by mawyatt
Mon Mar 16, 2020 4:55 am
Forum: Photography Through the Microscope
Topic: EPROM
Replies: 8
Views: 1131

Ah, so that's what those square cells along the edge, with silver centers, are for! I see these on lots of wafer elements, but this is the first time I saw them with wires soldered to them! Lou, Beautiful old EPROM chip in package image by JW!! The wires aren't soldered but themocompression bonded ...
by mawyatt
Wed Mar 11, 2020 5:16 pm
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

Chris, Sure, sorry for being so stubborn!! That's why I introduced a little Pink Floyd to help lighten things up in my last post :D Since I was asked to provide an LED model and measured LED data, which I'm delinquent on providing, here's a Cree XM-L2 LED model just created with SPICE using the defa...
by mawyatt
Wed Mar 11, 2020 10:43 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

LED is a DIODE

Peter, Here's a few LED references for you, many more are available. From Webster: https://www.merriam-webster.com/dictionary/led LED noun \ ˌel-(ˌ)ē-ˈdē \ Definition of LED (Entry 2 of 2) : a semiconductor diode that emits light when a voltage is applied to it and that is used especially in electro...
by mawyatt
Wed Mar 11, 2020 7:58 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

THIS ACTUALLY IS THE BASE of my suggestion that you can not use it on all LEDs and I kept calling out for the LED model you used in your "circuit". Peter, If the "circuit" you reference is the "Fast LED Strobe for Macro" thread https://www.photomacrography.net/forum/viewtopic.php?t=40999 This is cu...
by mawyatt
Wed Mar 11, 2020 7:34 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

One last thing, there is something called numerical analysis where you do not need an equation, as long as you have some empirical data (ie, the charts, the chart), you can compute it. Again, with that chart, you do not need an equation whether it is Shockley Equation, or Schottky, or even Einstein...
by mawyatt
Wed Mar 11, 2020 6:42 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

Since you claim to "know this kind of circuit", care to give us a detailed analysis of how it works?? Why many of the load characteristics don't matter. Best, Well, a simple word, it basically have sensing resistor, feeding back to comparator that turns of and off a transistor. But unlike you, I do...
by mawyatt
Wed Mar 11, 2020 6:32 am
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

Shockley Equation and Schottky . . . hahaha OK, my mistake, but it is irrelevant. Shockley and Schottky certainly are not irrelevant, maybe the person making these mistakes is irrelevant!! We are going in circle. Anyways, please do that exercise like I mentioned, it is as real and as hands on as it...
by mawyatt
Tue Mar 10, 2020 7:06 pm
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

Finally, I think I know why viktor got different result. I am calling you out for an answer. If you do not trust me, we can get someone here and send answers to that person. I don't know what is causing Viktor's results, since I don't have his devices and setup. My original comment was about lookin...
by mawyatt
Tue Mar 10, 2020 6:51 pm
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

Also, those scope captures, are they real thing with your tektroinic scope, if so, I really need something like it, the portable one is getting too limiting. Not sure what scope captures you are referring to, but the 2 identical scopes shown in the image are Tektronix 2465 analog scopes. These are ...
by mawyatt
Tue Mar 10, 2020 6:44 pm
Forum: Equipment Discussions
Topic: Building an LED light/flash
Replies: 92
Views: 8068

THIS ACTUALLY IS THE BASE of my suggestion that you can not use it on all LEDs and I kept calling out for the LED model you used in your "circuit". Peter, If the "circuit" you reference is the "Fast LED Strobe for Macro" thread https://www.photomacrography.net/forum/viewtopic.php?t=40999 This is cu...