I am designing high pass RL filter. R is 550 [Ohm], L is 220 [uH]. I calculated that time constant is therefore 0.0000004 [s] and -3 dB pulsation 2 500 000 and frequency 397 887 [Hz]. I put this on the breadboard and connected JDS 6600 signal generator and Rigol DS1054Z oscilloscope to test it. For testing I apply sine signal of 5 [V] (Vpp, amplitude) and varying frequency. As expected I observe decreased amplitudes of the signal at the output for low frequencies and increasing amplitudes for signals of increasing frequency. Using transfer function
|H(j omega)| = 1 / sqrt(1 + (1 / (omega tau)^2))
I calculated that 0.95 signal attenuation should happen at 1 210 781 Hz (|H(f=1210781)|=0.95) and that would mean that I should see about 4.75 V at this freq, but in practice I get this value at about 1 MHz.
Why do I see such a big difference?