https://oshwlab.com/wagiminator/78xx-replacement
https://hackaday.com/2022/09/05/the-7805-is-dead-long-live-the-7805/
I think the same.
Though I would prefer a real 7805 any time, if possible.
The 78xx series is so nice because of its simplicity, clean output (no RF noise or ripple; remember the caps and protective diode though) and robustness, not its efficiency.
With a generously sized heatsink, it will run for decades without failure.
Sure, the higher the input voltage, the higher the higher dissipation. But that’s how it works, it’s a linear regulator (in Germany, we also call it “Stabi”, from Stabilisator = stabilizer). It must compensate somehow, which causes thermal energy.
But on the other hand, the 78xx will keep the output voltage stable no matter what.
Remember, it can handle voltages up to 25-35v (7805, 7812 resp). So you technically could power you device with two car batteries at 13,8v each.
Btw, the recommended input voltage should be at least ~2,5v above the rated voltage.
So an 7812 should be operated with 14,5v.
Unfortunately, that’s not the case in practice.
Many developers traditionally used 13,8v (stabilized) as the power source for their products running with an 7812 inside, a voltage used by car batteries and lab power supplies and CB radio power supplies supplies.
That’s violating the datasheets, strictly speaking.
Because it’s merely 1,8v above, not 2,5v.
Anyway, I’m merely mentioning this because this article is about an 78xx replacement. Knowing that the reality didn’t stick to datasheets and specs might be helpful in troubleshooting.
Best regards, vy73,
Joshua
And many useful technical reply later
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We manufacture stir plates and home brewery controllers and we build our own PWM controllers in-house. I’ve gone the route of active components direct from China and was bitten hard by counterfeit parts and parts that just didn’t perform to spec. Because of my history with Chinese suppliers the last thing I’d trust direct from China is a voltage regulator. So these days everything comes from DigiKey. Sure, most still come from China but at least if the part is in their catalog it’s vetted by an importer or manufacturer and others are buying the exact same parts.
In one month I lost about $7,000 USD because of substandard SSRs. I even wrote an article about that one! https://www.kegkits.com/SSRs.htm
We still buy SSRs direct from China but only from one manufacturer I have history with.
And we still buy two different 12 VDC direct from China but these also come from one manufacturer I have history with. But any plug-in 12V power supply has poor regulation and I understand this. We also sell one of those 12V 1A power supplies on Amazon because they work well.
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