yeah, you really need some current limiting. i use open frame linear supplies for charging batteries, and set the current limit at the recommended charging current of the battery (foldback current limiting is very useful), but then again, i have a few of those kicking around the workshop. at least add a 10 ohm 5 watt resistor in series with the ba

A TMOS MTM7N45 (Q2) is used as a series pass element in a linear high voltage supply that accepts +275-V unregulated and produces 250 V regulated with foldback current limiting. A 15-V zener, D1, provides the dc reference for operational amplifier U1, whose other input is obtained from a fraction of the output voltage. UI drives Q3, which drives t

A TMOS MTM7N45 (Q2) is used as a series pass element in a linear high voltage supply that accepts +275-V unregulated and produces 250 V regulated with foldback current limiting. A 15-V zener, Dlf provides the dc reference for operational amplifier Ul, whose other input is obtained from a fraction of the output voltage. Ul drives Q3, which drives the gate of Q2.