Cadmium sulfide is a chemical compound with the formula CdS. Cadmium sulfide is yellow in colour and is a semiconductor. More here.
I’ve purchased a few heater-less vacuum tubes, that use CdS to provide photosensitive features, from an excellent Ebay seller, ven-tronics.
The tubes are as follows:
| ORP 50 (12.7mm x 38mm | 6MOhms in dark and 300KOhms in bright light) | |
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OAP 12 (2.38mm x 9.5mm) |
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ORP 60 (3.17mm x 12.7mm | 5MOhm in dark and 220KOhm in bright light) |
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ORP 63 (3.17mm x 25mm | 90KO in dark and 3KO lighted) |
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RCA 4403 (1MO dark and 360Ohms in bright light) |
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RCA 7536 () |
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RCA 7846 () |
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Pressler Cesium photocell () |
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