Without knowing exact requirements of this 48-to-12V converter, as a good starting point I can suggest a circuit based on 12V Zener diode .. see attached picture ..
ok. In that case you can use the circuit of IanP, but it dissipates a lot. (~3.6W for the resistor and max 1.2W for the zener) However it is a very low cost and simple solution. (you have to change the resistor for ~360 Ohm)
An other solution could be a SMPS. High efficienty, but more expensive (small coil + electronics)
**broken link removed**
dear IanP
i tried to use 4.7K but it doesn't supply enough current
when i but 470 ohm it supplied enough current but it became too hot,
do you have any recommendations
hello,any Schematic Diagram or Circuit Diagram Sir??and also its Component Values??Like resistor values..i need this 48vdc to 12vdc circuit too for my project...tnx in advance
hello,any Schematic Diagram or Circuit Diagram Sir??and also its Component Values??Like resistor values..i need this 48vdc to 12vdc circuit too for my project...tnx in advance
Use a series diode with your 12Volt Zener to correct for the Vbe of the pass transistor which will then give you 12Volts output.
Suitable transistor, as in an earlier post in this thread, would be the TIP31 or TIP41 and the series resistor for the Zener+Diode of the order of 3k3 ohms with a rating of 1/2 watts.
Be aware that this circuit has no current limiting so be careful of short circuits!