Two sine waves with different phases, LM324
Oscillateurs   /    Oscillators
Électronique / Electronic

In this project, you are going to make a circuit that oscillates two waves at approximately 1 kHz, each wave 90 degrees out of phase with respect to the other.

One oscillating wave (sine) connects to LED 1, and the other wave (cosine) connects to LED 2. LED 1 and LED 2 change in brightness in accordance with the swing of the waves.

You will notice that the varying brightness has a time lag between LED 1 and LED 2, an indication of a phase difference.

When you finish wiring, turn power ON.

In about 10 seconds, LED 1 and LED 2 light up continuously. After that, both LEDs start oscillation at approximately 1 Hz.

At any point of time, the brightness of LED 2 changes with a slight lag behind LED 1, or more accurately, with a 90-degree lagging phase.

Try to change the oscillating frequency by changing the values of R and C.

The OP amplifier U1A is an inverting amplifier. U1C and U1D are integration circuits.

U1B amplifies the sum of the outputs of U1 A, U1C, and U1D.

The output of U1C is a sine wave having travelled through the band pass filter, while the output of U1D is a cosine wave having travelled through the low pass filter.