Identify the role of the following components in this audio amplifier circuit: The 0.47 μF capacitor connected to the microphone The 220 k Ω and 27 k Ω resistor pair The 4.7 μF electrolytic capacitor connected across the 1.5 k Ω resistor The 33 μF electrolytic capacitor connected to the speaker The 47 μF electrolytic capacitor connected to the power supply railĪdditionally, answer the following questions concerning the circuit’s design: What configuration is each stage (common-base, common-collector, common-emitter)? Why not just use one transistor stage to drive the speaker? Why is an additional stage necessary? What might happen if the 47 μF “decoupling” capacitor were not in the circuit? Why does the second stage of the amplifier not need its own voltage divider to set bias voltage as the first stage does? The following schematic shows a simple, two-stage audio amplifier circuit: Transistor amplifiers are no exception to this rule. In order to successfully troubleshoot any electronic circuit to the component level, one must have a good understanding of each component’s function within the context of that circuit. How would you measure ripple using an oscilloscope? “Good-quality” power consists of DC within the proper voltage range of the amplifier circuit, with negligible ripple voltage.įollow-up question #1: suppose you discover that the “faulty” amplifier is in fact not receiving any input signal at all? Does this test exonerate the amplifier itself? How would might you simulate a proper input signal for the amplifier, for the purposes of testing it?įollow-up question #2: explain how to measure power supply ripple voltage, using only a digital multimeter. The rationale for checking the input signal should be easy to understand. Seeing the malfunction with your own eyes may illuminate the problem better than if you simply acted on someone else’s description, or worse yet your own assumptions. It is usually a good idea to verify the exact nature of the malfunction before proceeding with troubleshooting strategies, even if someone has already informed you of the problem. All audio signal cables (including the speaker cables) may be unplugged to provide access for your meter’s test probes.Īt what point in the system would you begin testing for the presence of an audio signal? Explain why you chose that point, and describe your subsequent actions based on the results of that test. Despite all these good indicators, though, no sound is heard from the speakers.īeing prepared at all times to troubleshoot electronic systems, you have a digital multimeter close by which you may use to check for the presence of audio signals (set the meter to measure AC millivolts). The CD player indicates the disk is being played, and that it is presently playing a song. ![]() All control knobs seem to be set to their proper positions, as well. ![]() All components in the system are turned on, as indicated by power lights on the front panels. Suppose this system has a problem: no sound at all coming out of either speaker. The CD player generates the audio signal to be amplified, while the equalizer/preamp modifies the tone of the signal to suit the listener’s preferences and the power amplifier provides adequate power to drive the speakers. Examine the following “component” stereo system closely:
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |