I'm trying to rectify an AC current at 220V. Many written tutorials don't mention any transformer before the diode bridge and many video tutorials use transformers that provide an output of 6V or more.
In my understanding, diodes can withstand only very small voltages in forward bias since current is an exponential function of voltage. With only two diodes working at the same time during each half cycle, every diode will get no less than 3V in case of a 6V transformer. If no transformer is present, each diode will have 110V across it.
An electrician I know stated that many power adapters (such used by laptops) use a transformer after the bridge, which would imply that the diode bridge is connected to the mains ! He also added that some diodes can withstand 1000V, like the 1N4007 diode (I even read that on some websites) but when reading the datasheet for the 1N4007 diode, 1000V is the maximum reverse voltage, not the forward one, and during rectification, the diode needs to work both ways, so it will hold in reverse bias but it would normally burn in forward bias.
Am I missing something or understanding something wrongly or are all the tutorials I came across wrong? And also how much voltage can a rectifier diode withstand in forward bias, isn't it very close to 0.7V?