How does high internal resistance make high voltage power supplies safe?

AI Thread Summary
High internal resistance in power supplies ensures that the terminal voltage remains low when compared to the external resistance. This occurs because the high internal resistance leads to a significant voltage drop across the internal components, resulting in a reduced terminal potential difference. Consequently, the current output is also minimized, enhancing safety during laboratory use. The design allows for high voltage supplies to be used without posing a significant risk of electric shock. Overall, high internal resistance effectively mitigates hazards associated with high voltage applications.
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Homework Statement


When the internal resistance is large in comparison to the external resistance, the terminal potential difference falls to a small value. This is used to make high voltage supplies safe for use in a laboratory. Explain how this makes the supply safe.

Homework Equations


Vterminal = EMF - Vinternal

The Attempt at a Solution


If the internal resistance is high, since Vinternal = I r, where r is the internal resistance, the Vinternal will be high. This means the Vterminal will be low. And because of the internal resistance, the current will also be low. So then what is the point of having a high voltage power supply?
 
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I have attached what I think is the solution. Please could you look at it and see if it makes sense and is right. Thanks
 

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