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Mzzed
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I am struggling to understand the voltages present in the circuit below. So as stated in the diagram, there is 30V AC at the secondary of the transformer, this is equivalent of 42.4Vpeak. The bridge rectifier changes this to DC and drops the voltage down to roughly 26.3Vpeak DC where each diode is assumed to have 0.7V drop. The zener voltage is 15V so there must be a 11.3V drop across R1 and R2 total. Then ground is indicated as seen on the far right, so there must be a 15V drop across the zener diode ZD1. ZD2 also has a zener voltage of 15v so the bottom output is -15V meaning there is a 15V drop across that zener diode as well... Adding up the total voltage drop across the circuit, that would be 45V... from a 42.4Vpeak source voltage.
How is the bottom rail able to be negative? and why does it seem like there is a 45V drop across the circuit where the supply is only 42.4Vpeak AC (30V RMS)?
How is the bottom rail able to be negative? and why does it seem like there is a 45V drop across the circuit where the supply is only 42.4Vpeak AC (30V RMS)?