Search found 580 matches

by Joseph
Thu Nov 23, 2017 5:25 pm
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 1510

Re: Another simple amp question

I refined my circuit today on LTspice. I added the emitter follower on the input like I was thinking earlier, and added another one to buffer the pull-up resistor. I was thinking about lowing the value of the 47ohm resistor since I noticed little or no actual effect by including it in the circuit at...
by Joseph
Mon Nov 20, 2017 5:51 pm
Forum: General Discussion
Topic: Another simple amp question
Replies: 16
Views: 1510

Re: Another simple amp question

I think adding another 2N3904 as an emmitter follower for the input would be good to try.
by Joseph
Wed Nov 15, 2017 2:42 pm
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 1145

Re: Iron wire inductor

I think I am probably in the knee region of figure 4 right now (at the last linked site). Yet after further looking at the graph, I think that isn't right. Since power is still a little over half of the rated output by my reckoning, operation has to be on the red (safe part) of the curve. I did noti...
by Joseph
Wed Nov 15, 2017 8:28 am
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 1145

Re: Iron wire inductor

I have two microwave ovens, one on power pulsing and the other also on that, but also given voltage reduction. I noticed some of my things needed much more pulsing and for much longer than ovens were set up for. My first oven ended up with stuck timer contacts from too much cycling. I made an extern...
by Joseph
Tue Nov 14, 2017 12:00 am
Forum: General Discussion
Topic: Microwave oven transformer... reversed.
Replies: 10
Views: 1971

Re: Microwave oven transformer... reversed.

Howdy, I had an old Texas Instruments calculator that appears to have predated the TI 30 that had a wall wart using a transformer like that. I seem to recall that it even regulated the output with just a zener diode. Presently I have a choke that I made with a roll of wire as the magnetic core. I wo...
by Joseph
Mon Nov 13, 2017 8:25 pm
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 1145

Re: Iron wire inductor

I had an inductor coil in mind that had a small inner diameter, and enough Iayering to make the outer diameter about ten times the inner, or more. Say ¼" inside, 2" outside diameter, and maybe something like 3" long. I haven't been a fan of iron or steel leads because of concerns about corrosion and...
by Joseph
Sat Oct 28, 2017 9:09 am
Forum: General Discussion
Topic: Iron wire inductor
Replies: 12
Views: 1145

Iron wire inductor

What if insulated iron, or silicon steel, for that matter, was made into an inductor so that the wire was to act as both the windings and the magnetic core? It seems like it probably was tried sometime within the past 200 years or so. The reasons it doesn't work, if it doesn't, could be a bit compli...
by Joseph
Fri Oct 27, 2017 8:17 pm
Forum: General Discussion
Topic: Microwave oven transformer... reversed.
Replies: 10
Views: 1971

Re: Microwave oven transformer... reversed.

I dont think he should remove the welds holding the core together just to put in 2 turns. I'd cut out the secondary winding with Plato wire cutters or a knife. Then feed through the new secondary. I once made a twelve Volt power supply that was resistant to damage from shorting out the 12V. It had a...
by Joseph
Fri Aug 25, 2017 2:08 pm
Forum: General Discussion
Topic: Effects of loss of analog TV broadcasting on viewing
Replies: 12
Views: 1490

Re: Effects of loss of analog TV broadcasting on viewing

My general picture quality was much better during predigital broadcast days also. I could get about seven TV stations but just two after the conversion. I didn't really mind a bit of snow, or resolution limits of the NTSC signal. Those two stations had five separate channels between them, but only t...
by Joseph
Fri Aug 25, 2017 7:20 am
Forum: General Discussion
Topic: Effects of loss of analog TV broadcasting on viewing
Replies: 12
Views: 1490

Effects of loss of analog TV broadcasting on viewing

Since the changeover from analog to digital over-the-air TV broadcasting, I have barely watched any TV. For a while before I got this tablet PC connected to DSL Internet, I used to get one digital channel on an eight inch portable digital-receiving TV. That was to see the weather radar on a major TV...
by Joseph
Fri Aug 25, 2017 7:10 am
Forum: General Discussion
Topic: What keeps me up late!
Replies: 48
Views: 5841

Re: What keeps me up late!

My guess that Billy Joel is a pretty good harmonica player, and can play it while at the piano.
by Joseph
Sun Apr 30, 2017 5:42 am
Forum: General Discussion
Topic: looking for a digital Fahrenheit sensor
Replies: 13
Views: 2269

Re: looking for a digital Fahrenheit sensor

well here is the thing.. i built a digital temp a few years ago using the ICL7107 and a LM34 sensor...the ICL7107 was set up as a volt meter.. it worked, but it never was linear.. and i did use the recommended parts. so i am tired of it..and want to use a Arduino nano and a temp sensor, i guess i c...
by Joseph
Tue Apr 25, 2017 5:41 pm
Forum: General Discussion
Topic: TA7205AP
Replies: 9
Views: 1683

Re: TA7205AP

I remember the troubleshooting guide said what some of the different tubes were that could cause the example bad raster picture shown. I was wondering why even though the tester I linked to looked familiar, it was lacking the display console that the ones in the store had. The 6NS7 does sound famili...
by Joseph
Sun Apr 23, 2017 4:39 am
Forum: General Discussion
Topic: TA7205AP
Replies: 9
Views: 1683

Re: TA7205AP

Hi Len,
I recall that troubleshooting guide now with those pictures of various faulty rasters!

http://tubedatabase.co/testers/hickok-533a
by Joseph
Thu Apr 20, 2017 5:18 pm
Forum: General Discussion
Topic: TA7205AP
Replies: 9
Views: 1683

Re: TA7205AP

Back in those days, even with relatively high parts and labor costs, it was more worthwhile to repair consumer electronics. It could more likely be that I bought two of the TA7205AP ICs for $20 because there is a good chance that I didn't know if one or both of the originals​ in the amplifier were b...