Very high voltage on HOT´s collector...

Hi, can anyone tell me what may cause the base-collector voltage to be over 1000V? If the HOT is connected B-C voltage is over 1000V and voltage at base is less than 1 volt, if i remove the HOT, B-C voltage drops to 112V and Base still is less than 1V.

also over 1000V... Can anyone tell me what is going on? What can cause these very high voltages?

Thanks.

Reply to
onyxx
Loading thread data ...

onyxx: The high voltages you are reading with your meter are a result of back emf as a result of fast switching of the transformer's input power.... that is why the voltage ratings for Collector to Base and Collector to Emitter have to be upwards to 1500 volts for these kinds of semiconductors that do the switching. You should not be measuring these points with your meter.... damage can easily result. Do a little reading a the website for this newsgroup at

formatting link
there, with some searching, you will find a wealth of pertinent information that will answer a lot of your questions as you continue to learn about electronics servicing.

--
Best Regards, 
Daniel Sofie 
 Click to see the full signature
Reply to
sofie

If you use a cheap meter, you will get false readings due to the 1200 volt P-P AC pulse @ the collector, when the HOT is conducting. You can damage you meter, or kill your T.V., if your not careful. Sky.

Voltage at chopper transistor´s collector (low voltage power supply)is also over 1000V... Can anyone tell me what is going on? What can cause these very high voltages?

Thanks.

Reply to
Skype_man

ElectronDepot website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.