When connecting a speaker system to an amplifier, it is advisable to check its maximum output power. Similar measurements may also be needed when setting up or repairing equipment. This is necessary in order to ensure good performance of the entire system.
Necessary
- - oscilloscope;
- - multimeter;
- - pointer tester.
Instructions
Step 1
Connect one of the amplifier channels to the speaker if you know that its rated power is expected to be higher. You can also use a dummy load whose impedance is equal to the impedance of the speakers. In this case, use a PEV-type resistor with a power of 10-100 W.
Step 2
Use an oscilloscope to measure the amplifier's output power. Apply a sinusoidal signal with a frequency of 100-200 Hz to the amplifier input, for example, you can simply play some musical composition. Begin to gradually increase the volume while observing the oscilloscope reading.
Step 3
Record the moment when at the output of the amplifier the output signal begins to be limited in amplitude and measure the voltage. Remember that when measuring the maximum output power in this way, you cannot apply a high frequency signal from the generator to the input of an amplifier that is connected to multi-way speaker systems. This could overload the midrange or tweeter.
Step 4
Calculate the power of your amplifier, which is the square of the output voltage times twice the resistance of the load or speaker.
Step 5
Use any voltmeter to measure the power of the amplifier if you don't have an oscilloscope at hand. For example, take a multimeter or a pointer tester. In this case, it is necessary to assemble a circuit that will allow any voltmeter to become a peak voltage meter. The source of the signal in this case will be the low-frequency master oscillator, i.e. the music signal at the input will not be able to give a reliable result.
Step 6
Connect a dummy load and a capacitor of 0.47-1.0 μF to the amplifier in parallel, and a diode for a voltage of 50 W in series, then measure the output voltage and calculate the power.
