Hello, I am an Environmental Engineer with very little knowledge of electrical engineering, yet I am working on a project and need a little help. I need to pulse DC current. I have a power supply that will be putting out about 15 vDC and I need to pulse this current at this same voltage. At minimum I need to pulse the current at one second intervals but it would be great if I could try a few other things like a sinusoidal wave or pulsing at different time intervals. Is there anything out there that I can put in the circuit that will allow me to do this? Perhaps something with a usb port, or something of the sort, so I can code in some different pulsing option with a nice graphical user interface? If there is something out there will it have restrictions on how many volt i can run through it? I will be running at about 15 vDC but I may potentially want to go as high as 40 or as low 3 volts. Thank you for any help you can offer.