Favourite parts with off-label uses?

Nice, I was trying to express this idea, but I was more focused on keeping the length of the tube long to limit diffusion of the H2O.

George H.

Reply to
George Herold
Loading thread data ...

Soft Scrub is great, practically an optical grade abrasive. It makes copper (or gold plated copper) all shiny without scratching.

I sometimes use a Scotchbrite pad with Softscrub to deburr and polish dremel'd boards, but that does scratch the beautiful gold a bit.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

I found a youtube that showed Hydrogen peroxide and muratic acid (swim pool variety), it work very well for me.

Mikek

Reply to
amdx

S-curve did not look so triangle-like as it was supposed to be.

t

rom

.

down.

h

Some tips, re: toner transfer method for making PCBs. Consumer-type laser p rinters are generally focused on producing sharp text, not graphics (like P CB patterns). Only some will be best for that. Based on visual judgments of printed fine detail by my fellow experts, I'd take a look at these color l asers: HP Color Laserjet Pro MFP M177fw (HP 130 toner set), American and EU market s HP Color Laserjet Pro MFP M476dw (HP 312 toner set), American model Canon i-Sensys MF8230Cn (Canon 731 toner set), EU model HP Color Laserjet Pro M452NW (HP 410 toner set), EU model HP Color Laserjet Pro M477FDW (HP 410 toner set), EU model

Mono lasers we've tested have not done as well as color lasers for graphics . Not that mono's couldn't in theory - perhaps the manufacturers assume peo ple only care about text quality on these lower-cost models. Also make sure the setting in the printer driver are optimal: (1) "toner saving" feature turned off (2) heavy or high-quality mode turned on.

Reply to
Rich S

With minimally vented or imperfectly sealed enclosure you have the problem that if it gets splashed with cold water on a hot day it cools rapdily and the air inside contracts and sucks surface water in.

Using the cable to vent the enclosure seems like a good scheme, assuming that air flows freely enough and it terminates in a dry location.

--
  Jasen.
Reply to
Jasen Betts

ore

h
e

s

.

le

nd out.

Talking with hams it seems they never trust sealing to keep an enclosure fr ee of moisture. After reading about a defect in a auto brake pressure swit ch impacting something else at the other end of the car I realized why. Th e pressure switch was sealed, but the switch itself developed a leak, not t o the outside, but to the also enclosed space with the wire which wicked it into the spaces between the strands. The brake fluid was carried to the o ther end of the vehicle where it came in contact with something that it the n messed up.

So if you have any insulated wires exiting a sealed enclosure, in the long term it is not sealed. I guess that's why they use those through the bulkh ead solid pins to pass signals in and out of a sealed box.

--
  Rick C. 

  -+- Get 1,000 miles of free Supercharging 
 Click to see the full signature
Reply to
Ricky C

An old TV HV rectifier tube, a 1B3 or whatever, makes a good high-voltage capacitor.

It makes a good HV amplifier too, with the input being the filament voltage. A little slow maybe. When I was a kid, I used to charge HV oil caps from a neon sign transformer. A 1B3 was the controlled rectifier to set the voltage, with a flashlight battery and a rheostat (with a long insulated shaft and a knob) for the filament supply.

NE2 type neon lamps make good transient supressors, relaxation oscillators, and noise sources.

PMTs have been used as random pulse sources, for example in radar jammers.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

Whoosh! Right back to just before where (this part of) the thread began.

It doesn't work if you don't get solid blacks from your laser printer. It doesn't work the same for apparently equivalent papers - it takes a lot of experiment to find one that works for you. There is paper that is specified and sold for this specific purpose, and it works well.

There are many other things that have to go just right too. A clothes iron is plagued with problems which is why I (and many others) use a modified laminator. Much more controllable.

CH

Reply to
Clifford Heath

printers are generally focused on producing sharp text, not graphics (like PCB patterns). Only some will be best for that. Based on visual judgments of printed fine detail by my fellow experts, I'd take a look at these color lasers:

ets

cs. Not that mono's couldn't in theory - perhaps the manufacturers assume p eople only care about text quality on these lower-cost models. Also make su re the setting in the printer driver are optimal: (1) "toner saving" featu re turned off (2) heavy or high-quality mode turned on.

Thanks Rich.

My frustration was that I had a working setup, reliable, used for a few years, that suddenly completely quit working for no apparent reason. Other than moving all the equipment to a new location, I was still using the same equipment, technique, and supplies.

So, I don't think it's the printer, though I experimented by changing cartridges, nor the paper -- I'm using the same paper from the same original pack -- and so forth.

Gerhard's probably right, the dry photoresist method is probably best, but I've had poor luck, historically, with photo methods.

A list of good laser printers that make dense prints is a handy thing for all these processes, thanks.

Cheers, James Arthur

Reply to
dagmargoodboat

Well I've done quite a bit of mucking around with 4 ERA-3's (96dB gain!) and nothing I've tried will stop it from oscillating. Because I used

33nF coupling caps, with the 50R matched impedance it oscillates about 200-300kHz.

During the few occasions where it was well-behaved I got really nice looking noise from the resistor source, with most of the density within

20mV of the origin, and a scope trace that barely changed in appearance between 10ms/div right up to 5ns/div.

It was all looking pretty ok for a while actually, until I noticed some noise spikes from the fan in my PSU getting to the output, so in addition to the 220nF decoupling caps on each stage, I added a 10uF aluminium electrolytic - and since I added that it takes off like a rocket at any bias level above 15mA.

I had to reduce the bias current below the recommended 40mA, because the maximum input level (13dBm) is just below the maximum output level (13.6dBm), and when it oscillates at full power that was enough to blow up MMIC 3&4 in the chain. Reduced current stopped them expiring, but doesn't stop the oscillation.

I tried a small can over the first stage but suspect the feedback path is on the board. An inductor in series with the first stage bias might help?

Pictures here (the noise is with the zener source):

You can see I used generic grid-punch prototyping PCB, with adhesive copper foil to make a ground plane on the back.

I think I'll just drop back to the zener source, two stages, and call it done... unless someone else has a better idea?

Clifford Heath.

Reply to
Clifford Heath

You can get cable with all of the spaces between the strands etc. filled not with air, but with some sort of gel. Very messy but probably worthwhile if you need a cable to be buried and want it to stay free of liquid water.

Reply to
Chris Jones

Back when there were more analogue RF building-block chips available, I used to get about 40X speedup by cascoding their RSSI current outputs.

I made an interesting lidar-style 3D scanner that way, using current-tuning of a diode laser plus a diffraction-grating gizmo to provide both a fast fine scan (20 pixels worth) and a triangle-wave FM waveform. The tri wave lets you measure both time-of-flight and Doppler, because their frequency offsets add on one slope and subtract on the other.

In lots of situations you can get excellent results by connecting a photodiode directly to the input of an MMIC amp with no coupling cap. The input is usually within a factor of 2 of 50 ohms, and the noise temperature may be as low as 100K.

Cascoding a solar cell can get you up to about 100 kHz bandwidth with unbeatable detection area and good linearity at high current.

Gate drivers are good for running small Cockroft-Walton generators for PMTs or APDs.

Some depletion pHEMTs will self-bias with the gate below the source, so you can use them with no bias resistors. For the lowest-noise applications, that saves some input capacitance, which helps. (You can't get them anymore, unfortunately.)

The monitor photodiode of a diode laser can be used as a temperature sensor--it's brazed to the same header as the laser, so it's super fast.

A quadrant photodiode will give a nice beam position indicator that's independent of the laser power if you just add and subtract diagonally opposite pairs of open circuit voltages.

1 | 2

-----

3 | 4

X = (1-4) - (2-3) Y = (1-4) + (2-3)

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs 
Principal Consultant 
 Click to see the full signature
Reply to
Phil Hobbs

WWII vintage bomber radio altimeters worked that way. Send a CW carrier that's triangle FM modulated, and mix the transmit and ground echo signals. The beat frequency is proportional to altitude.

I just did that in my new GHz o/e converter. The DC behavior of the MMIC is dreadful, so I have a separate low-frequency gain path to get clean DC-coupled step response.

MMICs have a lot of personality. You've got to test them to find out what. And hope MiniCircuits doesn't switch fabs.

--
John Larkin         Highland Technology, Inc 

Science teaches us to doubt. 
 Click to see the full signature
Reply to
jlarkin

Oh never mind. It just needed (much) better supply decoupling at the sensitive end. Working a treat now. Spectrum analysis next.

Clifford Heath.

Reply to
Clifford Heath

---------------------------------------

** Few WW2 bombers ever had them.

Only useful at low altitudes as a blind landing aid.

Also for deck landings, which did not involve bombers.

.... Phil

Reply to
Phil Allison

???????????, 13 ? ?????? 2020 ?., 18:34:49 UTC+3 ?? ?????????? Phil Hobbs ? ???????:

Erratum ?

INA330 with current output in simple PID controlled TEC (TO-8)

formatting link

Internal gate-source zener FDV301N in zerocross detector 100Hz

formatting link
formatting link

Reply to
plastcontrol.ru

That is how the airliner radio altimeters still work.

--

-TV
Reply to
Tauno Voipio

Tauno Voipio wrote in news:r7505i$5on$ snipped-for-privacy@dont-email.me:

Marker beacons are similar but very nearly outmoded by GPS.

They have a sound of each indicator. Pretty cool.

Reply to
DecadentLinuxUserNumeroUno

Laser self-mixing "radar" with triangle injection current Measuring Absolute Distance by Linear Frequency Sweeping

formatting link

Laser feedback interferometry: a tutorial on the self-mixing effect for coherent sensing

Reply to
plastcontrol.ru

Hmm well not the cable (carrying wires). I was picturing a long tube on the vent... it could be coiled inside the box.

So here's a 'back of the envelope' calculation question. The diffusion constant of H2O in air (STP) is about 0.3 cm^2/sec.

formatting link

So if I have a 10 cm (long) tube the time it takes for water to diffuse along it is about 200 seconds. t = len^2/(2*D). So how then do I calculate the number of water atoms at steady state that are diffusing along the tube?

Do I calculate the number of water atoms entering the front area of the tube, in one second. And then divide by 200?

George H.

Reply to
George Herold

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.