Timeline for L7805CV 5 V Voltage Regulator 1.5 A
Current License: CC BY-SA 3.0
6 events
| when toggle format | what | by | license | comment | |
|---|---|---|---|---|---|
| Aug 11, 2012 at 17:47 | comment | added | stevenvh | A TO-220 has a thermal resistance, case to ambient of 65 K/W, so at 700 mW ,and 20 °C ambient it should only be about 65 °C. That's only just too hot to touch. It shouldn't be very hot, unless "too hot to touch" is your definition of "very hot" :-). Did you supply 12 V to it? | |
| Aug 11, 2012 at 16:13 | comment | added | Gregory Ion | Before I wrote the comment I built the circuit to test what I just posted. At 50mA the TO220 is warm but at 100mA is very hot. You are right about total dissipation. | |
| Aug 11, 2012 at 7:00 | comment | added | stevenvh | No, it's 50mA times the voltage difference between input and output voltage = 50 mA x (12V - 5V) = 350 mA. The 250 mA is what the load will dissipate. 350 mA is what a tiny SOT-23 can dissipate, a TO-220 will do much more. | |
| Aug 11, 2012 at 6:57 | comment | added | Gregory Ion | Actually it is 5V x 50mA = 250mW. | |
| Aug 10, 2012 at 18:15 | comment | added | stevenvh | A heatsink for 350 mW??? | |
| Aug 10, 2012 at 17:52 | history | answered | Gregory Ion | CC BY-SA 3.0 |