{"product_id":"mullard-0a81-germanium-point-contact-crystal-set-diode-tested-oa81","title":"Mullard 0A81 Germanium Point Contact Crystal Set Diode Tested OA81","description":"\u003cp\u003eThis is one item of used Mullard OA81 diode recovered from a 1960s transistor radio. You might prefer to use one of these original larger germanium point-contact types if you're making a crystal set. These have all been tested for less than 500mV Vf at 0.89mA. The paint may have flaked a little in places and the picture shows a typical item. If your design specifies an OA91, the OA81 will do fine as according to the 1969 Mullard data book, the OA91 is just a physically smaller version.\u003c\/p\u003e\n\u003cp\u003eThere are various crystal set experiments and musings available on my websites:\u003cbr\u003e\u003cbr\u003e\u003ca href=\"https:\/\/www.interestingelectronics.com\/old\/henrys_interesting_electronics\/loud_crystal_set_radio\/loud_crystal_set_radio.htm\" title=\"A Good Loud Crystal Radio Design With Some Justifications And Digressions\"\u003eA Good Loud Crystal Radio Design With Some Justifications And Digressions\u003c\/a\u003e\u003cbr\u003e\u003cbr\u003e\u003ca href=\"https:\/\/www.interestingelectronics.com\/old\/henrys_interesting_electronics\/crystal_radio_v2\/crystal_set_radio_v2.htm\" title=\"The More Standard Parts Crystal Set Version 2\"\u003eThe More Standard Parts Crystal Set Version 2\u003c\/a\u003e\u003c\/p\u003e\n\u003cp\u003e\u003ca href=\"https:\/\/www.usefulcomponents.com\/main_contents\/projects\/choccy_block_crystal_radio\/choccy_block_crystal_radio.html\" title=\"https:\/\/www.usefulcomponents.com\/main_contents\/projects\/choccy_block_crystal_radio\/choccy_block_crystal_radio.html\"\u003eThe HJW Electronics Choccy Block Crystal Set Radio Kit CBCSRK-1T\u003c\/a\u003e\u003c\/p\u003e","brand":"Mullard","offers":[{"title":"Default Title","offer_id":58501260640640,"sku":null,"price":1.8,"currency_code":"GBP","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/1007\/2136\/1280\/files\/oa81_top_s.jpg?v=1791634633","url":"https:\/\/shop.usefulcomponents.com\/products\/mullard-0a81-germanium-point-contact-crystal-set-diode-tested-oa81","provider":"HJW Electronics","version":"1.0","type":"link"}