2011年1月25日 · This is an excellent way to understand the theory. A linear regulator will use a transistor to step the voltage down as an inline resistor(the transistor can be modeled as a variable resistance) with feedback changing its resistance to …

2019年8月9日 · The 78xx series does have adjustable versions, but the LM7805 is not one of these: the 05 stands for a fixed output voltage of 5V. What the circuit does is build a virtual ground. That does work, but it's very undesirable from a regulation quality point of view. (The LM7805 is not symmetrical in what it can quickly adjust if the load changes.

2019年4月25日 · i dont have LT1021-5 in my LTspice but have LT1021A + i already brought a chip LM7805 I ask lot of questions .. you may get angry at times but I still wont leave you until I'm clear on the topic, when satisfied I will give you a like, become your follower and install a small statue of your's in my bedroom as one of my gods, and pray to it.

2020年5月1日 · The LM7805 is much more forgiving. There's no power dissipation advantage in dropping one of these in place of a 7805, not at all, under some conditions just the opposite. There are switching regulators that you can use such as the Murata OKI-78SR-5/1.5-W36-C which actually are very efficient and are (more-or-less) drop-in replacements allowing ...

2013年4月17日 · LM7805 "spice model" Thread starter Bagotdt; Start date Apr 17, 2013; Status Not open for further replies. B.

2015年11月14日 · An LM7805 does not require a minimum load, however it draws a few mA itself, even with no load. If the output voltage drops to near zero with just the regulator, that implies that the solar cell is getting very little light (in a dim room), is too small or is defective.

(16 Ohms x 250 mA = 4 V. 12 V - 4 V = 8V for the LM7805, which is lots more than 7 V, so that's fine). With 16 Ohms the voltage drop across the LM7805 will be 3 V at 250 mA and 4.6 V at 150 mA, so the power converted to heat in the LM7805 will be 0.75 W or 0.69 W, which is a lot less than the 1.75 W or 1.05 W with no resistor.

Please understand that i am actually a really beginner in electronics. I found a really nice topic on how to create a 5V DC from a 9v power supply. All is ok. But in order to smooth out ripple, the

Use an LM7809 to produce a 9V regulated output; and then feed this signal to the input of LM7805. 7809 will drop about 3V and 7805 about 5V, as opposed to a single 7805 burning 7V. Share

I'm using an LM7805 in voltage regulator mode. Vin is 15V Vout is 5V (regulated) The attached load draws 200mA How to calculate how much power the LM7805 would dissipate in this setup (and whethe...