CD4066 switch resistance.


Joined Dec 20, 2007
TheDag, here is the regulator:
Since the resistor from the output to the ADJ terminal is 240 ohms then an expensive LM117 regulator must be used because the 240 ohm resistor provides its minimum load current of 5mA.
But a less expensive LM317 uses a 120 ohm resistor and the other resistor also must be halved.


Joined Dec 20, 2007
Nearly all LM317 calculators on the internet see the 240 ohm resistor on National Semiconductor's first page of their datasheet and on nearly every other page. But they don't notice that is shows the more expensive LM117.


Thread Starter


Joined Jan 1, 2010
Thanks for all, BTW I think I know how this switch works (not sure enough) :
One pad connecting to microcontroller, and one pad connected to battery+.
And when the switch short this 2 pads, the volts power up the microcontroller and the device is powered up.
Is this correct?



Joined Dec 20, 2007
Wtf, you are here to laugh at me?
I was not laughing at you, instead I did not understand what you said.
Many people on these forums speak different languages.

You said, "fit for this way" which does not make sense in English.

Maybe you mean, "will the circuit do what I want?"