I have noticed something at my workbench, am I close?
When using a mains power transformer, I have noticed
that they all sag under load. Some are worse than others,
this we all know. However, it seems to me that, for instance,
a transformer RATED for 3A @24v, the unloaded voltage (30v) will sag
less as a greater load is introduced. I might get a 4v sag
with the first .25A load, but only a 6v sag with a 3A load, just as an example.
Am I seeing this correctly?
In the aforementioned transformer example, a 24v AC secondary
will be over 42v rectified & filtered. This is still a little high for
an LM317, and way over the top for an LM338.
Is there a way to deliberately introduce a little voltage sag before the LM317/LM350/LM338?
Perhaps a small bulb or resister either just before, or just after the bridge?
How does one solve this problem when the voltage is just a little too high?
This application/project is just for small bench-top power supplies, and little projects around
the home and shop, either fixed voltage, or variable.
When using a mains power transformer, I have noticed
that they all sag under load. Some are worse than others,
this we all know. However, it seems to me that, for instance,
a transformer RATED for 3A @24v, the unloaded voltage (30v) will sag
less as a greater load is introduced. I might get a 4v sag
with the first .25A load, but only a 6v sag with a 3A load, just as an example.
Am I seeing this correctly?
In the aforementioned transformer example, a 24v AC secondary
will be over 42v rectified & filtered. This is still a little high for
an LM317, and way over the top for an LM338.
Is there a way to deliberately introduce a little voltage sag before the LM317/LM350/LM338?
Perhaps a small bulb or resister either just before, or just after the bridge?
How does one solve this problem when the voltage is just a little too high?
This application/project is just for small bench-top power supplies, and little projects around
the home and shop, either fixed voltage, or variable.