Precision Condenser Micrometer Dial PW Series PW-1 PW-2 PW-3 PW-4

• alternative name: National Toy Co.
• Brand: Thrillbox

The National PW Series Dials were introduced in 1934, along with the National HRO receiver. It is a combination of a geared variable condenser with a micrometer dial. The worm gear drive has a ratio of 20 to 1. It was available with a single or ganged condenser.

PW-1 Single Section Condenser   $13.50                                                                 PW-2 Two Section Condenser      $17.00                                                                 PW-3 Three Section Condenser    $20.50                                                                 PW-4 Four Section Condenser      $ 24.00

The PW Series of Dials were most famously used on the National HRO series of receivers, from the original through the HRO-60. A variation of the dial was even used in the 1960s on the solid-state HRO-500. However, they were also used on other National receivers, such as, the 1-10, 1-10A, and HFS.

In questo link sono elencati 445 modelli, di cui 284 con immagini e 189 con schemi.
Elenco delle radio e altri apparecchi della National Company; Cambridge & Malden (MA)