I succumbed to temptation and bought some more stuff from goldmine elec.com. I just couldn’t pass up some of the deals they had.
I got a whole 5000 reel of 1N5245B 15 volt zener diodes; they’ll probably last till the end of my life, unless I give them away. The whole reel cost only $7.00!
I got a bag of 2000 diodes, FDH400 type. They’re 150 volt, half amp. I saw a high voltage project where the builder put a whole bunch of 1 amp rectifiers in series to get several thousand volts. With 2000 of these, I could put scores in series to get a HV rectifier, and still have hundreds left over to play with. On a more practical note, they may work just fine for rectifying the 120 VAC for small AC line operated devices such as motion sensors, remote control receivers, LED lights, etc. Two in series could handle 300 volts peak reverse voltage.
I got a reel of 500 2 to 6 pF trimmer capacitors. Probably tiny and hard to solder. They sIould be great for tuning FM microphones. I should build one up to get a feel for their capabilities.
I got several of the bargain bags of five TO-3 power transistors marked with house numbers. These are typically part numbers used internally, and cannot be cross referenced to an industry part number. But the ubiquitous 2N3055 is about the bottom end of the power transistor performance list, so if the house numbered transistors are silicon and are used in a similar circuit, they should work. Of course I’ll have to sort them out to NPNs and PNPs. Some may even be something else, such as voltage regulators. I haven’t received them yet, so I don’t know yet (I received them – see update below).
I got a few other miscellaneous things, too. I’m looking forward to getting the package early this week. I usually count the parts I buy, but there are so many I think it’ll take too much time. The parts on reels should be easy to count.
Update June 16 – I received the box this afternoon. I looked at the reels and saw that they’re dated 1999, so I guess they should be called new, old stock. They were stamped with an ACCEPTADO stamp, so my guess is that they were from a maquiladora or ‘sweat shop’ in Mexico.
The half dozen bargain bags of 5 transistors are very interesting. In addition to transistors, I received several 3-terminal regulators. There was a LM150K which is the same, but better military specs than the LM350K. Then I got several 7703403YA ‘transistors’, which I found out are the same as LM137K, a hi reliability mil spec adjustable 3-terminal negative regulator, again the same as, but better specs than the LM337K. The National Semi LM1xx linears were a lot more expensive than the LM3xx because they were the wider ‘military’ temperature range.
I did get some odd power transistors. One was a MJ900 PNP power Darlington , beta of 1000 minimum at 3 amps. Another was a MJ13081 NPN high voltage (Vce = 450V) probably for the horizontal output of a TV.
Some of the cases were marked MC7815K, which is simply a 15 volt, 3 terminal regulator. Some of the labels were illegible so I couldn’t tell what they were. I’ll have to check them with the ohmmeter to find out if they are NPN, PNP, and if they are a transistor or whatever.
One had dust on it, so it must’ve been removed from some equipment. Almost all of the leads were bent somewhat. All of the date codes were from the 1980s or earlier – they’ve been sitting around for decades. Also, I have to check to see if they are good; they could be out of spec or nonfunctional.
All except 1 bag had an IR TR01A transistor. This is a high power (90W) germanium transistor, meant for audio power amps like car radios. The replacement transistors for it now sell for more than 25 dollars (US) apiece; old germanium parts are becoming very rare nowadays. So I got a new old stock germanium power transistor for a dollar and a quarter, plus 4 other parts in these bargain bags. Such a deal! I think the bags were easily worth the $1.25 I paid.
I bought a couple dozen of the “real thing” 2N2222 metal cased transistors, five for $1.25 (a quarter apiece). This is not much less than what the price is for new (actually new old stock) ones – the 2N2222 was superseded by the 2N2222A, so they are no longer made*. They were all labeled with the big M for Motorola.
The leads had all been bent so they would fit into a socket. This leads me to believe that they are ‘culls’, transistors that have been tested and were rejected or not selected for some reason. This may or may not be bad. I measured the gain of all of them with a cheapo DMM, and they were within normal limits, from 300 down to 170, but most were in the mid 200s. If the test was for high gain, above 300, then the remaining ones will probably not be ‘rejects’, they’re just not the highest gain ones, okay for most purposes.
I also bought a bunch of butt splices or connectors. These are the yellow ones with the silicone gel inside. The two wires to be spliced are cut even and the insulation is left on the wires. They are inserted into the two holes in the connector, and the yellow button is squeezed with a pliers. This forces a metal finger with a slot in the center down onto each of the wires. The slot cuts off the insulation and makes a gas tight contact with the wire. The silicone gell surrounds the splice so that water and corrosion are kept out of the splice. These are made for outdoor use, but can be used anywhere.
* No longer manufactured, but still it is possible that the semi company can label a currently made transistor as a 2N2222. Believe it or not, there is a gray market for counterfeit transistors and semi’s in other countries.
More later.
Update Aug 19 – I got a bag of 100 blue LEDs in a milk white epoxy package, for $8.00. That’s only 8 cents apiece, cheap! I’ve been thinking about colored LEDs, and I’ve come to the conclusion that the colored LEDs I use don’t need to be in a clear case and the light doesn’t need to be concentrated in a beam. This is because almost all colored LEDs I use are for decoration, not for illumination. White LEDs, on the other hand, are used for illumination and should have a light beam.
These blue LEDs have a diffused light, which is good for decoration.