#!/usr/bin/perl
use warnings;
use strict;
use feature qw(say);

my @voltages = ('0.940V', "0.940V\n", "0.940V\r\n",
                '0.740V', "0.740V\n", "0.740V\r\n");

for my $voltage (@voltages) {
    say "Yes 1" if $voltage == "0.940V";
    say "Yes 2" if $voltage =~  /^0\.9[0-4]+V$/;
    say "Yes 3" if $voltage =~  /94/;
    say "Yes 4" if $voltage =~  /^0.*V$/;
    say "Yes 5" if $voltage =~  /V$/;
}
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Note that == is for numbers, so you can change 1 to $voltage == 0.94.

Output:

Argument "0.940V" isn't numeric in numeric eq (==) at ./1.pl line 16.
Argument "0.940V" isn't numeric in numeric eq (==) at ./1.pl line 16.
Yes 1
Yes 2
Yes 3
Yes 4
Yes 5
Argument "0.940V\n" isn't numeric in numeric eq (==) at ./1.pl line 16
+.
Yes 1
Yes 2
Yes 3
Yes 4
Yes 5
Argument "0.940V\r\n" isn't numeric in numeric eq (==) at ./1.pl line 
+16.
Yes 1
Yes 3
Argument "0.740V" isn't numeric in numeric eq (==) at ./1.pl line 16.
Yes 4
Yes 5
Argument "0.740V\n" isn't numeric in numeric eq (==) at ./1.pl line 16
+.
Yes 4
Yes 5
Argument "0.740V\r\n" isn't numeric in numeric eq (==) at ./1.pl line 
+16.
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Try printing what really is in the array:

use Data::Dumper;
$Data::Dumper::Useqq = 1;
print Dumper \@voltages;
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Update: Added the \r\n strings.