Turntable DC Supply 24V Very Complex/Strange

ridikas

Member
2011-11-25 9:16 pm
Need help to double check this schematic so no boo boos happen. It's rather complex and somewhat strange. It will be powering a turntable's motor. Thanks guys.

The unmarked capacitor is 4.7uF electrolytic.
 

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Mooly

Administrator
Paid Member
2007-09-15 8:14 am
You'll struggle to get a clean and regulated 24 volt rail from an input of around 25 volts DC (18vac * 1.414) using a linear regulator.

This looks more like an active ripple filter with zener limiter that stops the output going above 24 volts or should the input happen to be a bit higher.
 

Mooly

Administrator
Paid Member
2007-09-15 8:14 am
Except the input voltage isn't high enough to get it to regulate well......

Just calculate the zener current and available base current to the NPN device. Ultimately though, I suspect non of this matters for its intended application as a motor PSU.