Sensitive Audio Power Meter Schematic Circuit Diagram
As a follow-up to the simple audio power meter described in [1], the author has developed a more sensitive version. In practice, you rarely use more than 1 watt of audio power in a normal living-room environment. The only time most people use more is at a party when they want to show how loud their stereo system is, in which case peaks of more than 10 W are not uncommon. With this circuit, the dual LED starts to light up green at around 0.1 watts into 8 ohms (0.2 watts into 4 ohms). Naturally, this depends on the specific type of LED that is used. Here it is essential to use a low-current type. The capacitor is first charged via D1 and then discharged via the green LED.
This voltage-doubler effect is via the green LED. With this voltage-doubler effect level of 1 watt, the transistor limits the current through the green LED and the red LED conducts enough to produce an orange hue. The red color predominates above 5 watts. Of course, you can also use two separate, ‘normal’ LEDs. However, this arrangement cannot generate an orange hue. For any testing that may be necessary, you should use a generator with a DC-coupled output. If there is a capacitor in the output path, it can cause misleading results.
The Source Component. If the quality of the signal from your source component is low, this affects the rest of your stereo system, even if everything else is of the highest quality. …
- The Speakers. …
- The Amplifier. …
- Other Factors.