3 ms·
The turn on levels I measured were much smaller in discrepancy than that; the silicon diodes were clipping at 0.55 V, while the LEDs were only slightly higher,
by cushychicken 11y ago
The turn on levels I measured were much smaller in discrepancy than that; the silicon diodes were clipping at 0.55 V, while the LEDs were only slightly higher, at about 0.8 V. Made me wonder if I was measuring them incorrectly.
- ableal 11y agoThat sounds OK, if a bit low. Perhaps the resistors are large, or you might be diverting some current through a low(ish) impedance voltmeter, but those should be rare nowadays. The trick with diodes is that the curve is exponential - so for a "0.7V" diode, and pulling numbers out of the air, you can get 0.3V for nanoamp currents, or 1.0V for power-station currents (for the brief moment before it melts ;-) The real equation is very simple, if anyone wants to play. For instance, it's well explained here, midway down the page: http://www.allaboutcircuits.com/textbook/semiconductors/chpt-3/introduction-to-diodes-and-rectifiers/ http://www.allaboutcircuits.com/textbook/semiconductors/chpt...
- cushychicken 11y agoThat's a good point; the DMM I used could have just been extrapolating "turnon" to a certain current. I'll have to check the DMM's specs.