I've experimented with LM7805 analogs from NTE (the NTE960), and the large tab on top makes it obvious how to dissipate generated heat.
However, NTE also makes an LM7805 analog in a TO92 package (the NTE950). I'm a sometimes hobbyist, and I don't really know how one goes about handling the heat when inputting, say, 7 volts to such a packaged chip. Can someone point me to a good discussion or tutorial on this topic? Thanks.
TO-92 isn't meant to be a high-power-dissipating package. 180°C/W isn't going to get you too far, and there often isn't exposed metal to help get heat out.
That being said, there are some slip-on heatsinks available that can get you a few more milliwatts. Other techniques include drawing heat through the legs into the PCB, having a copper pad on the PCB and lead-forming the device to be bent over and touching it (with a clip and some thermal compound). Improvement to 60°C/W is possible.
Having some airflow helps too - a small fan can improve the power handling of the device (especially when combined with a heatsink of some form).
The ironic thing about this blog is that the originator is named Wakefield. If i recall correctly, Wakefield is also the name of a popular heatsink manufacturer...
In order to know which device (78L05, 78M05, 7805 or 78H05) to use, one needs to know something about how much current will pass through and how much voltage will fall across the regulator. Device thermal, current and voltage limitations are found in the mfg's datasheets. If, after doing calculations (power dissipation) and consulting the datasheets, you determine that you need a heatsink, you'll have to obtain heatsink mfg data in order to select an appropriate sink. As a sometime experimenter, overkill on the sink is a good idea which will save your regulator and maybe whatever it feeds. GL
