Voltage Regulator Trouble

[PIG80085]

Hi,
I have a 78L05 taking in 15.5 VDC but only putting out something like 0.6VDC. Have I blown it somehow?? Any way way to know that if I replace it with another 78L05 I won't get the same problem? Things to look out for? Sorry guys not a lot of practical experience here lol!!
Thanks,
Pig.

 

[ThermalRunaway]

As long as you're sure that you're testing the correct pins, then it certainly sounds as if the device has been destroyed. What type of equipment is the device being used in? The 78L05 is only designed to output 100mA max. Is it getting hot or does it remain cold?

With regard to repeat failures, the best thing to do is ensure that your 5V rail is not shorted to ground. Be aware that if it is, it might be the regulator itself that is providing the path - remove it and test the 5V rail again. Of course, depending on the application (is it your personal project), you might be overdriving the device. It can provide a max of 100mA so if you're asking for more, it's going to melt.

Brian

 

[Souper man]

you could use a LM7805 if you need more than 100mA. they are quite handy especially when they have a 1 amp output

 

[ThermalRunaway]

you could use a LM7805 if you need more than 100mA. they are quite handy especially when they have a 1 amp output

Yes but it'll start to get very hot before it gets anywhere near a 1amp output, especially with such a high input voltage. LM7805's in high current applications should be fitted with an adequate heat sink.

Brian

 

[Hero999]

Also an LM78L05 can't supply 100mA with a 15V input, look at the datasheet.

 

[mneary]

It's pretty difficult to destroy a 78L05 if it's hooked up properly.

If you want answers instead of guesses, please provide the following details:

How much current are you demanding?
Is it getting hot?

 

[PIG80085]

I'm trying to power a PIC 16F627. The circuit is loosely based on . The project is to be able to control a hobby servo using this.

With the chip not in place, the reg outputs about 2.5V, as opposed to the 0.6V when it's in. The 78L05 gets quite hot whether the PIC is in there or not too so I take it I need to replace it.

Thanks for the replies.
Pig.

 

[3v0]

You did not answer mneary's questions.

How much current are you demanding?
Is it getting hot?

 

[audioguru]

An LM78L05 and any other kind of linear regulator IC shuts down if it gets too hot and limits the current if it tries to get too high.

 

[mneary]

There are other loads on 5V such as the servo. These loads are too much. For example even a small hobby servo can require one ampere.

You forgot the required capacitors C1, C2, and C3. You put them in backwards.

Your PIC is installed backwards.

Your battery is backwards.