Connect with us

Can I use 78l05 replace lm2931?

Discussion in 'General Electronics Discussion' started by circuit12, Sep 19, 2019.

Scroll to continue with content
  1. circuit12


    Jun 12, 2018
    Good day,
    I'm fabricating an undertaking I got as PCB+panel, sourcing my very own parts. It takes a clock supported through CD40106 and runs a CD4017. The consecutive yields of the CD4017 make a programmable arrangement of voltages that go to a LM358-based yield organize. The full schematic can be seen here. I simply acknowledged I didn't source the LM2931, which structures the +5V line for the computerized ICs. I checked the datasheet and resembles it's only a low-dropout 5V controller appraised at 100mA. Should great 78L05 voltage regulator fit the bill as a substitution for simply fueling 4XXX rationale? I'm practically certain it ought to be fine yet thought it's smarter to inquire. Here's the important piece of the schematic:
    Likewise, I thought of utilizing a TL072 rather than the LM358 as I have a lot of these.
    I have had a go at reaching the PCB maker with a past task additionally from him, however got no answer so I think I'll get everything dealt with speedier by simply asking here and making a few alterations all alone.
    PS: The LM358 stage is only the typical 100k/100k adding blender for the CD4017 yields and afterward 100k/100k support with 15pF in the criticism way and 330R at the yield jack.
  2. circuit12


    Jun 12, 2018
    Any advice or suggest will be appreciated!

    Thank you in advance!
  3. Bluejets


    Oct 5, 2014
    Either might get a bit hot under the collar with such a large voltage difference.
    Cannot see why you need low dropout, perhaps it is simply physical size.
    I'd be getting a much lower power in supply like 6V to use either of the ones you quote.
  4. Audioguru


    Sep 24, 2016
    The LM2931 low dropout regulator was probably in the original circuit so that a 6V battery can be used. Your 78L05 might shut down when it gets too hot since it must throw away the power of the 12V - 5V= 7V difference that causes heat.

    The LM358 was used because its datasheet shows a minimum supply voltage is 3V and it works fine at 5V. The datasheet for the TL072 shows that it does not work when its supply is less than 7V and they recommend 10V minimum.

    You should always read the datasheets when you substitute parts.
Ask a Question
Want to reply to this thread or ask your own question?
You'll need to choose a username for the site, which only take a couple of moments (here). After that, you can post your question and our members will help you out.
Electronics Point Logo
Continue to site
Quote of the day