Hello,
Im attaching a 150W inverter ckt. Check it. Explain, how the overload section works.
Im attaching a 150W inverter ckt. Check it. Explain, how the overload section works.
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If it is a comparator, see, the inverting terminal is grounded. and the non-inverting is connected to your so called sense resistor. The R20 is placed in the DC side of the transformer (12V side). So, the current passing through it and hence the voltage across it will be a DC.Part of it is a comparator measuring input current across R20, a sense resistor of 0.001Ω pretty much in the center of the schematic. R20 is probably a wide trace on the circuit board, or a something that looks like a thick wire jumper.
ok. but how the opamp decides the over load situation???R20 is indeed a sense resistor. The transformer mirrors current in the secondary via the primary, be it at some ratio.
ThanQ thatoneguy. Thats what i want. one morething.Looking at it again, it appears that the TL081 is being run as an op amp rather than a comparator, I missed the feedback.
So the output of the TL081 is a voltage that increases with the current increase. The actual overload action appears to happen with the 4013-II flip flop. Once the voltage on the output of the comparator is at what the FF considers "Logic High", it will shut down the inverter by !Q going low on the input of 4093-I schmitt trigger AND gate, closing the path from the oscillator to the output MOSFETs.
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