How to make an adjustable unregulated DC converter

An adjustable unregulated DC converter, also known as a variable unregulated DC power supply, is a type of power supply that provides a fixed DC n output that can be manually adjusted by the user.
The main advantage of an adjustable unregulated DC converter is its simplicity and cost-effectiveness compared to regulated DC converters. However, it lacks the ability to maintain a stable output voltage in the presence of varying load conditions or input voltage fluctuations. Therefore, its use is generally limited to applications where a precise and constant voltage is not critical, or when voltage regulation is not required.