Newcomers to the electronics hobby may not know of latchup. It happens to ICs for various reasons and can result in a short usually between the power supply rails! There is plenty of material on the internet about it for reading.
I did just find an easy method of demonstrating it! Take a half dozen numitrons, hook them up to '595 shift registers and let the inputs float, omit smoothing or decoupling caps. Because of the floating inputs the display will usually shift around in a beautiful dazzle! But eventually will latch up and cook your ICs! Even if you have a microcontroller driving the inputs.. it might not come up to output state fast enough to prevent a latchup, and the driver ICs will just sit there and cook themselves. An easy trap to get into for a newcomer not familiar. The spikes in the power rail caused by the rapid on/off sequence causes this. A smoothing capacitor pretty much fixes it and a couple of 100nf decoupling capacitors will get rid of it entirely. Use decoupling caps on each IC and you should never see this. An excuse to buy a thermal camera and make a video? hmm.. Be well! Regards, -Moses -- You received this message because you are subscribed to the Google Groups "neonixie-l" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web, visit https://groups.google.com/d/msgid/neonixie-l/0e00cdd2-70e9-462c-9db5-c86f363d091bn%40googlegroups.com.
