LM317T LM317 Voltage Regulator Adjustable IC 1.5A 1.2V to 37V TO-220(Pack of 30pcs)

I acquired a non-working transceiver that had some "substitutions" installed for the pair of RF final output FETs by a previous "tech". Although the "touted-as-heavier-duty" output FETs WERE rated slightly more "power", they were rated for 55V instead of the 100V rating of the IRF-520s. Too much RF voltage peaks are likely what killed the "substitutions". In many cases it is best to trust the design engineers, and stick with the OEM part number that the service manual calls for. Just my opinion, of course. These worked well for me (careful bias adjustments were also done to ensure long-term reliability)

Let’s be real—there are sleeker, more efficient transistors out there… but the TIP31C? It’s the Chevy 350 small-block of general-purpose BJTs. It’s rugged, it’s simple, and it’ll push through heat, current, and amateur mistakes like a champ.I grabbed a pack of these to throw into:A DIY audio amplifier project (classic transistor push-pull),A linear power supply I was repairing,And even a high-power LED dimmer test circuit—and yep, it handled it all just fine.The C variant means it’s the high-voltage version of the TIP31 line—can handle up to 100V and 3A if you’ve got a decent heat sink strapped on. Great for switching, signal amplification, and good ol' analog control circuits. If you’re into learning by building, this one’s your friend.Why It Slaps:TO-220 package = easy to mount, easy to cool, breadboard-friendly (with a breakout)Handles high voltage & current loads without blinking (with proper thermal planning)Works great for PWM, amplifiers, relays, motors, and LED banksCheap and available—perfect for experimenting and prototypingWhat Could Be Better:Needs a good heat sink at anything over 1A—this thing will get toastyBJT means base current draw—if you're coming from MOSFETs, plan your resistorsNo extras in the packaging—no mounting hardware, no datasheet (but hey, it’s online)TL;DR:The ALLECIN TIP31C is a tough, no-frills NPN silicon power transistor for your mid-to-high power needs. It’s not fancy. It’s not surface mount. But it’s reliable, affordable, and ready for abuse—which makes it a perfect staple for DIY electronics and educational builds.It’s the kind of transistor that forgives your mistakes and teaches you something.

I started by using them as a pull-down with a resistor pull-up to Vcc. Doing it that way made me have another stage of inverter before driving a MOSFET gate to get the logic sense correct. I Found I could instead tie the collector to Vcc and use a 1k resistor pull-down on the emitter and still get a good high out. That way I didn't need the additional level of inversion.

The Allecin TIP41 100V 6A NPN Darlington power transistor worked well for me. My wife has a LED-lighted magnifying glass/lamp that died; the wall wart power supply died. A replacement power supply also did not work, so I purchased some parts-including these TIP41s-to build a 50 mA current source to drive the LEDs. I grabbed a TIP 41, built a little current source into the lamp housing, and fired it up. The LEDs came up just like they were supposed to at roughly the correct brightness. So, the TIP41 worked just as it was supposed to. However, note that the TIP41 transistors came loose in a little plastic box with no ESD protection. Given this, the transistors could all be damaged from ESD, and, if they work immediately, they could fail later from a latent defect. For that I remove a star. These days TIP41s seem to be a cheap ‘popcorn’ part sourced from many different vendors at a cheap price. The cases all have a ‘WS’ marking with a logo that I had never seen before, so I assume these are all parts sourced from China, and they might not meet requirements specified by TI or Motorola (ON Semi), and could be of very low quality, with very poor reliability (especially given no ESD protection). However, the parts were/are cheap, and my application is a non-critical application; if the TIP41 dies, I will just replace it in the circuit. Note also that given that the application is non-critical, I did not bother to test the parts, and I took no measurements and performed no testing on the current source that I built other than to confirm the brightness of the LEDs was about right. I buttoned up the light, and the wife is happy; end of story. Please allow me to emphasize again that I did not test the parts or the circuit, other than confirm that the LED brightness was about right, and thus have no clue regarding the quality or reliability of the parts. The one TIP41 that I used seemed to work correctly. I would not recommend their use in a critical application.

It arrived quickly and the logic level MOS FET worked well with the Raspberry Pico. I used 100 ohm resistor in series with the GPIO Pin to gate and a 10 K ohm from gate to ground to help with noise.

I used this optocoupler to repair a... pinball machine! This part replaced a 4N25 optocoupler on the pinball machine's motor controller circuit board. Once installed, the machine powered-up and worked perfectly. I like that the parts were well packaged and arrived quickly and I like that the parts came in a 6-pack (in case I need one in the future, as I have three other machines that use 4N25's). Delighted customer!