Output clamping diodes:When do we need them???

[Elvee]

Originally posted by Piercarlo


Is simple: imagine a power amp throttling about to half maximum output voltage and playng consistent bass content which usually require current beefing from output devices. In case of sudden disconnection of output cables, especially if long and connected to complex crossover, a voltage spike that may occur may be insufficient to activate the usual clamping C-E diodes ma enough to reverse breakdown the B-E junction of output devices and damage it (usually shorting it).

The spike occurs at the output cables, not the amplifier output. The amplifier is completely safe in this situation.
LV

[Piercarlo]

Originally posted by Elvee


The spike occurs at the output cables, not the amplifier output. The amplifier is completely safe in this situation.
LV

Sure of that? Why?

Piercarlo

[Elvee]

Originally posted by Piercarlo


Sure of that? Why?

Piercarlo

Because the voltage spike occurs on the inductance, when it is disconnected , and by definition, at that time, it is.... not anymore connected to the amplifier, which is therefore isolated from any consequences.
And if the spike is high enough to generate a spark that closes the circuit again, the current finds the way it followed before the break, and the overvoltage is quenched automatically.
LV

[Piercarlo]

Originally posted by Elvee
Because the voltage spike occurs on the inductance (...) and the overvoltage is quenched automatically.
LV

You are right but you are also too trustful in being on the bliss side of Murphy's law....

Hi
Piercarlo