# Period and Frequency

Oh, wait. I made it better.

These charts show how period, frequency, and the speed of light are related to each other, in scientific and compact units.

Period is measured in seconds, frequency is measures in Hertz (cycles per second), and the distance of light travelled during one period is measured in meters (it is also known as the wavelength). The equation for wavelength is:

λ = c / ν

Where λ is the wavelength in meters, c is the speed of light in meters per second, and ν is the frequency of the wave in Hertz (cycles per second).

Wavelengths between 400 nanometers (nm) for violet light to 700 nm for red light are the visible component of the electromagnetic spectrum. The frequency of red light, on the low end of the visible spectrum, is about 430 terahertz (THz); whereas violet light, on the high end of the visible spectrum, is around 750 THz.

# Frequency response

So I pumped a 1 kHz square wave into my DTL OR gate and observed the behaviour with my scope!

The square wave is in yellow, and the blue is the output signal.

You can see the output doesn’t drop back to zero quite as fast as the input.

You can see on the multi-meter to the right that the current draw is about 5.83 mA. That’s consistent with my earlier measurements given a duty cycle of 50%.

And you can see in the following photo that the frequency response of the circuit is rubbish. If you go much above about 10 kHz the output just stays “on”.