PicoMite VGA check


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phil99

Guru

Joined: 11/02/2018
Location: Australia
Posts: 496
Posted: 12:28pm 21 Jan 2022      

Impedance match is only important for long cables - tens to hundreds of meters. No visible problems on short cables.
Clipping diodes are only needed on very old cheap CRT monitors that have inadequate beam current limiting. I have not found a LCD monitor that can't cope with up to 1.5V.

With just a 220 ohm resistor in series with the 75 ohm input, I measure a Pico pin voltage of 2.2V. This gives a pin impedance of around 150 ohms, something to add to the circuit simulation.