I studied circuit diagrams of some computer ATX power supplies. Some of them have got a Zener diode at the very end of 5V stand by line.
The picture shows endpoint of the circuit - the SMPS is on the left (outside of the picture), then there are two capacitors, a resistor and a Zener diode - all parallel to the circuit. The 5 Volt output is on the top right of the picture. I expect the capacitors filter the output, the resistor is necessary to provide some minimum load in order to let the SMPS regulation work correctly. But what is the purpose of that Zener diode? It is rated 6V2, i.e. 24% higher than nominal output voltage. Is it some kind of a protection in case of regulation malfunction? And will it really protect the load from overvoltage? And if so, why is so much higher valued than nominal 5 V?