belax
Member level 2
Hello.
I need to make a small power supply (5V, 50mA) for microcontroller and other controlling circuit.
I have only two points: 300V and GND. 300V is from rectifier and ballast capacitor, so 300V is not stabilized.
I wanted to use this circuit
, where in my place Uvx will be about 300V. But in such circuit the power dissipation on the transistor will be about 295*0,05 = 14W. It is a lot.
So my question is: How to make a power supply which will not produce so much heat and will be relatively cheap(for example only resistors, capacitors, one or two transistors, zeners,...).
Thank you very much.
I need to make a small power supply (5V, 50mA) for microcontroller and other controlling circuit.
I have only two points: 300V and GND. 300V is from rectifier and ballast capacitor, so 300V is not stabilized.
I wanted to use this circuit
, where in my place Uvx will be about 300V. But in such circuit the power dissipation on the transistor will be about 295*0,05 = 14W. It is a lot.
So my question is: How to make a power supply which will not produce so much heat and will be relatively cheap(for example only resistors, capacitors, one or two transistors, zeners,...).
Thank you very much.