![]() ![]() In response, Mullard then changed their production process so that the OC71’s had a opaque silicone encapsulation of the die as opposed to translucent to protect their “new found” market for photo transistors. Engineers,not being entirely stupid caught onto this and just scraped the black paint off an OC71 to make an OCP71 equivalent and save 10 shillings. ![]() ![]() Somewhere down the line, it was realised that photo-transistors could actually be a useful device, so Mullard introduced the OCP71 photo transistor ( bit of a clue in the naming convention here ) which as far as everyone could make out was an OC71 transistor but without the black paint and priced at a premium 17 shillings and six pence, over twice the price. The device was light sensitive, so to stop the photo-transistor effect the glass enclosure was spray painted with black paint. Mullard OC71 germanium transistor tested at 70 degrees reads 80 hfe uses in Rangemaster, fuzz boxes, radios, effects units, etc cut from working item & not. The OC71 devices were manufactured in a glass enclosure with the die protected by a filling of transparent silicone inside for mechanical protection. Semiconductor: OC71 (OC 71) - TRANSISTOR GERMANIUM PNP / 32V / 10mA / 0.125W. If R2 <3kX and Re2 1 kX, then for the OC71 transistor, a1 < 014 and we can write xo ' xn 112a1 The condition for maintenance of oscillations is obtained. In these days, transistors were shipped individually ( at least in small quantities ) in long thin cardboard packages which in these days not only had the part number printed on the carton but the resale price as well ( 7 shillings and 6 pence in pre decimal currency for an OC71 if memory serves me correctly ). Details Item Number OC71 Item Condition New Price £12.50 (inc VAT £15.00) Options Quantity Add to Cart Next product PNP Germanium TO1 Black Glass 20V 10mA. At that time, Mullard was popular as an original supplier of germanium transistors in the UK with the classic OC71 transistor. Ah – germanium transistors, that takes me back. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |