I am looking for a chip that will enable me to input 3-12 V DC on 2 pins (+ and ground input), to get as output on 2 other pins, the exact voltage i put in those previous 2 input pins (+ and ground output) and to have a 5th pin, that if i put in a 3-12 V DC signal - Will turn on and off the electricity that goes between the previous 4 pins (+ and ground input and output).

I understand that maybe such a chip can be found on Motorola chip series MC140xx or 74HCxx or on the LMxxx (which is not Motorola, but another manufacturer, that starts with the letter N - i forgot its name).

Anyway - i need the chip to be as less expensive as possible.

Can anyone help me?

Thanks, Roi.

  • \$\begingroup\$ How much current will be drawn by the load (what ever is connected to the "2 other pins")? \$\endgroup\$
    – The Photon
    Jul 2, 2013 at 16:28
  • \$\begingroup\$ Does it have to be a chip? How quick does it need to be able to switch the circuits open and closed? \$\endgroup\$
    – Andy aka
    Jul 2, 2013 at 17:51
  • \$\begingroup\$ How about an analog switch (CD4066, etc)? As others are asking, figuring out the precise part requires knowing more about your requirement. Andy seems to perhaps be hinting towards a mechanical or solid-state relay, which gives you some immunity from the details of the switched circuit, at some cost and slowness. \$\endgroup\$ Jul 2, 2013 at 18:34
  • \$\begingroup\$ Do you really need to switch the ground? \$\endgroup\$
    – Tut
    Aug 1, 2013 at 19:30

1 Answer 1


The simplest soution which will have no voltage drop is a relay.

  • \$\begingroup\$ The current drawn will not be more than 3-4 amps. It is for a 2-3S LiPo with a few servos. It does not have to be a chip. It has to be not big and inexpensive. It has to switch between open and close only several times a minutes - no speed issue regarding the on/off function. \$\endgroup\$ Jul 2, 2013 at 18:55
  • \$\begingroup\$ I am trying to build a circuit to protect my 1000 mAh 3S LiPos, from over discharging. I am using also an Arduino and Low voltage LiPo alarm buzzers - and at the end point i have several small servos. I think that the problems with all these chips, is that although on the logic and analog side, they do exactly what i need, but they will not can't stand such a current as the LiPos let out. So i started searching for relays - but ones that have DC voltage of around 3-20V, not only for logic, but also 3-20 V DC for load - are rare and expensive. Do you have any idea for a solution? \$\endgroup\$ Jul 2, 2013 at 21:35

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