testing a voltage regulator

[tab a]

This is in regards to the L78MR05 but the theory I'm interested in, I'm guessing would apply to others.

What's the purpose of the 'delay' cap on pin 2?

Pins 4 and 5 are 5V outputs. If the input voltage and the ground are correct, will the outputs be correct IRRESPECTIVE of any problems in the circuits downstream from 4 and 5 (barring 4 or 5 being shorted to ground?)? In other words, if voltages at 4 and 5 are wrong, is it highly likely the regulator is bad?

Sorry if this seems really basic, but it's where I am on the learning curve!

Thanks.

 

[eng1]

I've heard of this chip from your post, but I have a datasheet on my pc. Pin 5 is the output (regulated voltage, referred to ground). Pin 3 is an auxiliary output that generates a reset pulse for micro controllers.
Most modern micro controllers have built-in circuitry for the power-up reset. The should be no problem using this chip as an usual 3-terminal regulator for most applications? What do you connect to the output?
You must measure the voltage between pin 5 and ground.

 

[tab a]

I think you mean pin 4 is aux reset?

I don't want to use it as a 3 terminal--it's already in a circuit, using all 5 terminals.

Just trying to find out if my PRESUMPTIONS about my test results, and the theory behind them, make sense.

Thanks.

 

[eng1]

I think you mean pin 4 is aux reset?

Of course, you're right. Pin 3 is ground

I post the block diagram for anybody whot may read this thread.


EDIT: do you have the datasheet? they show some useful waveforms and data for understanding the operation of the IC.