Tuesday, July 19, 2011

Class A Buffer pre-amplifier

A unit which is often useful, if we need to isolate, in sound circuits, two stage between them. Then we can use this circuit which has an amplified unit, which gain X1, we do not use total negative feedback, only local, with the result that distortion remains at a very low level. Matching must be done with great care to the types of transistors, resistor between them. There must also be thermal union between the transistors, as well as the diodes LED D1-2 with the transistor Q5 and Q2 respectively

List of Part

R1= 560 ohms C1-2= 100uF 25V Q2-4= BC560C
R2=  47Kohms C3-4= 47uF 25V Q3-5= BC550C
R3=  2.2Kohms C6= 1nF 63V ΜΚΤ Q6= BC560C
R4-7= 1Kohms C7-8= 100nF 63V ΜΚΤ Q7= BC550C
R5-6-10= 100ohms C9-10= 100nF 63V ΜΚΤ J1= 10pin Connector
R8-9= 47ohms D1-2= LED RED 5mm
R11-12= 10ohms Q1= BF 245C All Resistors is 1/4W 1%

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