10-03-2021, 09:56 AM
The whole idea of teaching that diodes, you make the anode positive, the cathode negative, seems strange to me... An ideal diode, after all, you would never BE able to do that because an ideal diode turns on with zero volts when passing forward current. You could only ever impose a voltage across it in the reverse direction.
If you connect a DC voltmeter across a diode in a rectifying circuit, you'd find the average voltage across it is anode negative, cathode positive.
Yes, there is a huge anomaly with Zener diodes, in normal use you make the cathode positive and the anode negative (why?? After all, a gas-filled voltage stabiliser you make the anode positive, the cathode negative). Even more with the TL431, which is an IC but the manufacturers call it a 'programmable Zener' and thus again, what they call the anode, you have to use as negative terminal.
Andy, yes agree completely (though the legend does have D9 beside it, they'd know to fit the diode because of a parts list showing what D9 is). Unfortunately, we can't change the legend, we're stuck with it.
If you connect a DC voltmeter across a diode in a rectifying circuit, you'd find the average voltage across it is anode negative, cathode positive.
Yes, there is a huge anomaly with Zener diodes, in normal use you make the cathode positive and the anode negative (why?? After all, a gas-filled voltage stabiliser you make the anode positive, the cathode negative). Even more with the TL431, which is an IC but the manufacturers call it a 'programmable Zener' and thus again, what they call the anode, you have to use as negative terminal.
Andy, yes agree completely (though the legend does have D9 beside it, they'd know to fit the diode because of a parts list showing what D9 is). Unfortunately, we can't change the legend, we're stuck with it.
