This circuit diagram is of an Atari 2600. I have circled the components that I want to know about. Can you please tell me what they are and why are they used here?

enter image description here

  • \$\begingroup\$ It's labeled right on the schematic, with an arrow pointing to your red circle at the bottom right. \$\endgroup\$ Aug 17, 2021 at 10:27
  • \$\begingroup\$ Offtopic but, Is that schematic hand-drawn? \$\endgroup\$ Aug 18, 2021 at 3:45
  • \$\begingroup\$ No @MightyBeard007. I saw about thus in a youtube video from the channel computerphile. From there I searched on the internet and found the schematic. \$\endgroup\$ Aug 18, 2021 at 5:08

1 Answer 1


The ic is a CD4050 hex buffer according to the schematic. This device basically 'strengthens' as in the output has a better current drive capability vs the logic signals from the TIA chip. The 4 buffers along with the resistors for a DAC (digital to analog converter) used to generate what I would assume is the color/video signal.

The CD4050 is a common and cheap ic.

  • \$\begingroup\$ The buffer used in digital electronics is used to pass the exact input to output so how does it strengthen the logic signals from the TIA chip? \$\endgroup\$ Aug 17, 2021 at 9:48
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    \$\begingroup\$ It isn't passing through the input to output like a wire, it's an active device which copies the input to the output, the output drivers in the buffer are probably stronger than those in the TIA. \$\endgroup\$
    – Colin
    Aug 17, 2021 at 10:01
  • \$\begingroup\$ Thanks @Colin. I was under the assumption that buffer works as a wire just passing. Your comment helped. I will look more into it. \$\endgroup\$ Aug 17, 2021 at 10:39

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