Get the first n characters of a large file with PowerShell

You can read at the byte level with Get-Content like so:

$bytes = Get-Content .\files.txt -Encoding byte -TotalCount 200
[System.Text.Encoding]::Unicode.GetString($bytes)

If the log file is ASCII you can simplify this to:

[char[]](Get-Content .\files.txt -Encoding byte -TotalCount 200)