In this experiment, a light organ fed off of an AC power supply was built and tested for
Different sources such as music, and varying frequencies were fed through
the circuit and voltage, impedance, and resistance were measured.
Lights containing 5
watt bulbs were used, and the power source was measured to be 115.5v.
Initially, the resistance through Resisters 1, 2, 3, and 4 were found to be 0.98kΩ, 1.34kΩ,
1.34kΩ, and 4.63kΩ, respectively.
The theoretical values for these transistors were 1kΩ,
2kΩ, 2kΩ, and 4.7kΩ.
These measurements are slightly low – especially through
resistors 2 and 3 - however, due to the alternating current of the circuit, the theoretical
values for resistance are merely an average.
for a schematic of the circuit.
Using the average values given for the resistance of the resistors, the total resistances
through the RC networks were found to be 760.9428Ω, 1228.2609Ω, 1403.6526Ω, and
These numbers make sense, as the lowest resistance is the
low-pass filter, and the highest resistance results from the high-pass filter.
The voltage drops through each of the SCR’s (silicon controlled rectifiers) were
measured and found to be 115.7V through SCR1, 115.8V through SCR2, and 115.5V
The total available voltage from the power source was 115.5V, and with
error of the measuring device, these measurements prove the light organ to be an efficient