| 摘要 |
PURPOSE:To limit a current at a load short time to prevent destruction of elements and make output impedance small by providing a negative feedback circuit between the connection point of a current limiting element, which is connected to the output side, and a load and the input terminal of an amplifier. CONSTITUTION:Current limiting resistance R01 is connected between amplifier 2 and head phone 3, and variable resistance Rf for negative feedback is connected between the connection point of resistance R01 and head phone 3 and the input terminal of amplifier 2. Signals applied to input terminal 1 are supplied to amplifier 2 through resistance R4, capacitor C1 and resistance R1 and are amplified there by the two-stage amplifier circuit consisting of transistor circuits Q1, Q2 and Q3 and the amplifier circuit consisting of transistors Q4 and Q5 of push-pull emitter follower and have the current limited properly by current limiting resistance R01 and are supplied to head phone 3. |
