Home
Help
Search
Login
Register1
Beginners / Re: How Can I check Horizontal output transistor with lcr-t4 meter?
« Last post by wasedadoc on Today at 12:19:46 pm »Datasheet for 2SC6090 has no mention of any collector-emitter diode.
Recent Posts
2
Buy/Sell/Wanted / Re: Canceled Because Thread All Shit Up by "tggzzz"
« Last post by tatel on Today at 12:18:12 pm »I wonder whether ebay seller sqwarrel will continue to sell the devices https://www.ebay.com/usr/sqwarrel
The listings he linked in this thread have been ended on Tue, April 23, but not those in the link you just provided. Well, I don't really care. A pity, but this guy obviously needs professional help. Not speaking about EE.
3
RF, Microwave, Ham Radio / Re: Problem with Inductor Self Resonant Frequency
« Last post by shabaz on Today at 12:15:34 pm »Hi,
If it's a one-off, then a hand-wound air-core inductor could be an option, it wouldn't be very large. Coil64 software is quite accurate, and 0.7 mm wire wound around an AA cell would only need about 22 turns to reach 5 uH. The software also provides a SRF calculation, and it would be > 30 MHz at those types of dimensions.
If it's a one-off, then a hand-wound air-core inductor could be an option, it wouldn't be very large. Coil64 software is quite accurate, and 0.7 mm wire wound around an AA cell would only need about 22 turns to reach 5 uH. The software also provides a SRF calculation, and it would be > 30 MHz at those types of dimensions.
4
Test Equipment / Re: Siglent Bench DMMs SDM3065X, SDM3055 and SDM3045X
« Last post by rolfdegen on Today at 12:15:01 pm »You can use a 1.5V battery as a reference voltage source for a few hours of measurement time ? The battery idle voltage is constant and is not charged by the measuring device. Since I don't have a 1V or 2V reference voltage source, I thought of a 1.5V battery to test the measuring range at 2V.
5
FPGA / Re: How to drive wheel on FPGA?
« Last post by NobikaNg on Today at 12:12:10 pm »Thank you for your reply. Actually, I am taking a VHDL course that requires me to define a topic and apply the FPGA knowledge I have learned in this course. I have also done experiments like controlling the blinking of LEDs. I initially chose the obstacle avoidance car as the topic because I had some knowledge of electronics and detectors from another embedded systems course, and I wanted to try to apply it in this course. However, I am finding this problem to be much more difficult than I imagined, but it should also be very interesting to complete.
6
RF, Microwave, Ham Radio / Re: fake MPF102s from AliExpress
« Last post by graybeard on Today at 12:11:46 pm »What I got were remarked NPN BJTs, not JFETs. See the attached images.
Did you test them in a circuit, too? Asking because my universal tester (similar with yours, but an older version) sometimes misidentifies certain parts.
I checked them with my desk meter. It showed the two PN junctions and no conduction from collector to emitter. They are NPN BJTs.
7
Beginners / Re: Automatic golf ball dispenser
« Last post by Maclarkson on Today at 12:10:45 pm »Ok so I 
8)have now bought a second hand 3d printer to make the housing. Infact I’ll just print the whole thing from scratch!! And the journey continues. I used a microphone by the way. Works well but not for kids who can’t hit the ball hard enough to get it to make a loud enough sound. Oh well I guess they will just have to do it the old fashioned way.
8)have now bought a second hand 3d printer to make the housing. Infact I’ll just print the whole thing from scratch!! And the journey continues. I used a microphone by the way. Works well but not for kids who can’t hit the ball hard enough to get it to make a loud enough sound. Oh well I guess they will just have to do it the old fashioned way.8
Beginners / Re: LM199 10V reference
« Last post by Kleinstein on Today at 12:10:43 pm »The histrogram looks reasonable, about what one expects.
Using the offset trim pot for a fine adjust of the ref . voltage is however not a good idea. The OP-amps offset is temperature dependent (about proportional to absolute temperature). So adding a significant shift from there is effecting the TC. The zero adjustment at the OP-amps should only be used for the OP-amps offset.
Using the offset trim pot for a fine adjust of the ref . voltage is however not a good idea. The OP-amps offset is temperature dependent (about proportional to absolute temperature). So adding a significant shift from there is effecting the TC. The zero adjustment at the OP-amps should only be used for the OP-amps offset.
9
Other Equipment & Products / Re: Which 3M static shielded bag
« Last post by Shock on Today at 12:08:20 pm »How tight is the fit? I'm torn over 5 x 8" (#30058) vs 6 x 10" (300610). If the drives are about 6" long and 1" deep that would leave about 1" for the ziplock space. So as long as they aren't super tight 5" wide, sounds ok. Are your bags 5" or 5.9" aka 6"?
10
RF, Microwave, Ham Radio / Re: Problem with Inductor Self Resonant Frequency
« Last post by bittumbler on Today at 12:07:29 pm »Hi Tim,
my problem is, that around 18MHz the combined inductor starts to resonate / become a capacitor. That is about the SRF of the 2.2uH parts.
So adding the smaller inductors in series seems to make no difference.
I was hoping to have somewhat of an inductor left until maybe 100Mhz.
My "probe" is a pogo-pin soldered to an SMA connector. Calibration was done at the SMA cable.
Matthias
my problem is, that around 18MHz the combined inductor starts to resonate / become a capacitor. That is about the SRF of the 2.2uH parts.
So adding the smaller inductors in series seems to make no difference.
I was hoping to have somewhat of an inductor left until maybe 100Mhz.
My "probe" is a pogo-pin soldered to an SMA connector. Calibration was done at the SMA cable.
Matthias