Yes and on the secondary side if they have a transformer.are they regulated by transistors in PWM mode?
They don't necessarily involve a transformer. How about you pony up a schematic and we can use that as a basis of discussion. The usual regulation device is a field effect transistor. These are preferred for many applications because of their low ON-resistance. BJTs can be used in boost converters when there is no convenient voltage source to turn on a FET.Switched Mode PS: Is it regulated on the primary side of transformer? I don't think a good idea on the secondary side. Also, are they regulated by transistors in PWM mode?
I tried to get a schematic but maybe my search skills? It is a Craftsman P/N700994 120 vac in 18vdc, 2.2 A outThey don't necessarily involve a transformer. How about you pony up a schematic and we can use that as a basis of discussion. The usual regulation device is a field effect transistor. These are preferred for many applications because of their low ON-resistance. BJTs can be used in boost converters when there is no convenient voltage source to turn on a FET.
Yes and on the secondary side if they have a transformer.
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Thanks. It looks like the transistors are on the primary i.e. 120 V side. Also there is a 100uF 400v CAPACITOR which seems to confirm this. I can post a pic if it helps.
If that is the case there is no apriori reason why this should be an SMPS (Switched Mode Power Supply). More likely it is a transformer,rectifier, and capacitor and it might or might not have any subsequent regulation. Motors don't necessarily care about regulated voltage, they run on just about any form of currentI tried to get a schematic but maybe my search skills? It is a Craftsman P/N700994 120 vac in 18vdc, 2.2 A out