Electrolytic Detector No. 1286 Improved

Etheric Electric Co. No. 1286 Improved Electrolytic Detector. This detector appears to be identical to the I.W.T. Wireless Electrolytic Detector and the Franklin Electric Novelty Electrolytic Detector.

(In the 1909–1912 period it was common for small New York-area wireless jobbers and catalog houses to private-label the same manufactured item (or simply reuse the same electrotype illustration and boilerplate copy). One maker or jobber almost certainly produced the detector (or the plates for the ads), and the others sold it under their own letterhead and list numbers.)

Basic electrolytic detector construction (bare-point type):

• A small cup (often platinum or carbon) containing dilute nitric or sulfuric acid (commonly ~20%).
• An extremely fine platinum wire (Wollaston wire—a platinum core inside a silver sheath, with only the tip exposed) whose end just dips into the electrolyte.
• A small battery and potentiometer to apply a carefully adjusted bias voltage so the cell is polarized (tiny gas bubbles form on the fine wire tip, raising its resistance).
• Headphones in series.

When a radio-frequency signal arrives, it depolarizes the tip, lowering resistance and allowing a pulse of current through the headphones. The bias current then re-polarizes the cell, making it self-restoring. It could detect extremely weak signals and was one of the first detectors capable of receiving amplitude-modulated (voice/music) signals—Fessenden used it for his famous 1906 Christmas broadcast.

Practical characteristics:

• Extremely sensitive when properly adjusted.
• Required frequent readjustment of the wire depth and potentiometer.
• Sensitive to vibration, temperature changes, and strong static (which could dissolve the fine wire tip quickly).
• Not ideal for shipboard use because of motion; better suited to fixed land stations.
• Largely superseded by crystal detectors (more stable, no liquid or battery bias) by the early-to-mid 1910s, and then by vacuum-tube detectors.

Here you find 4 models, 4 with images and 0 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.
All listed radios etc. from Etheric Electric Co.; New York City, New York