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						| Full-wave 
						rectifier |  
						|  |  
						| Introduced 
						in 1941 |  
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						| 
							
								
									| 1 | 2 | 3 | 4 | base |  
									| a1 | f | f | a2 | B4 |  |  
						|  |  
						|  |  
						| 
							
								| De 
								buizen werden verkocht door verkoper A. Jacobse, 
								Voorstraat 72 in Utrecht (ESRI), rond 1941; ze werden 
								ook verkocht in door Radio Groeneveld in Amsterdam in 1943. De interne afwerking 
								is nogal slordig. 
								De buis is te gebruiken als een 506 of 1823. 
								Er werd gesuggereerd dat Amerikaanse buizen 
								werden omgesokkeld maar de gemeten waardes 
								sluiten dat uit. |  
								| These 
								tubes were sold by A. Jacobse, Voorstraat 72 in 
								Utrecht (ESRI), around 1941 and also by Radio Groeneveld in Amsterdam in 
								1943. The internal 
								structure looks a bit messy. It can be used as a 
								506 or 
								1823 equivalent. It was suggested that American 
								tubes were converted to make this tube but the 
								measured data speak against this. |  |  |  |  |