Simple audio amplifier LM307 A741

As shown in FIG simple audio amplifier circuit. Using the integrated op-amp configuration of audio amplifier is stable, easy to negative feedback, so it is easy to get equaliza
Simple audio amplifier LM307 A741 - schematic

tion characteristics. In addition, crosstalk between channels is small, it is also very easy to mix multiple input channels. Figure (a) shows a circuit using a dual power supply (Vs 15V), with the phase-inverting input terminal, respectively, to ground the static balance resistance, the input signal Vi by the 0.1 F coupling capacitor into LM307N-inverting input terminal (Cited 3 feet). The signal source, the input resistance of about 1M, and therefore the equivalent load is light. The circuit voltage is about 101 times magnification, and has good dynamic characteristics. Figure (b) shows a circuit using a single power supply, because the DC level signal problem does not exist in the AC amplifier, so this power supply is desirable. In this circuit, the audio signal via a coupling capacitor C K and resistor R1 fed, A741C inverting input (pin 2). The figure shows that the circuit for DC component is introduced 100% negative feedback (c DC component is quite open), so the offset voltage without amplification. The voltage of the circuit magnification: Av -R2/R1 -1000 (ie 60dB). It should be emphasized that: R1, R2 and capacitor C having low frequency attenuation and phase shift effect, when the signal frequency is low, may be appropriate to increase the capacitance C of capacity.

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