NE555 pulse modulator is an electronic board generates continously square wave in different amplitudes and different frequancy bands to be used in the DIY projects needed square wave. The modulator is able to generate a square wave signals from 1 Hz to 200 kHz.

Usage of the Modulator:

There are 2 trimpots on the board. The one places on the left hand side increases the frequency with clockwise rotation, decreases in the opposite direction. The other one placed on the right hand side increases the duty cycle by the same way. You will find a jumper and 4 frequency headers on the board. These headers start from low frequencies to high frequencies. You can choose the frequency scale by wiring the jumper to one of these headers. Frequency bands are 1 Hz - 50 Hz, 50 Hz-1 KHz, 1KHz-10KHz, 10KHz-200KHz.