Hello fellow physics friends (alliteration: always a strong opener). I am writing today because I find myself struggling to complete something which ostensibly doesn't seem that difficult to the average physics undergrad working in a lab. However, electronics and circuits are definitely a weakness of mine. So I come to you all in the hopes of some resolution. Basically I need to create a simple circuit that will drive a laser diode. We will have a 6V battery which supplies the current necessary to drive the laser and in the circuit I want a fixed resistor (such that the current never exceeds a pre-set maximum -- for the lasers sake) and then a variable resistor to attenuate the current if need be. In addition I'd like to place an ammeter to measure the current downstream of the resistor(s) and finally I will attach the laser diode leads in order to draw current from the circuit. Now I've got the details of how I'm going to make everything work it's simply the circuit which is an issue for me. I've attached a picture of a recent attempt I made and I shall explain my (flawed) logic in the hopes someone can elucidate the correct way for me. So I was told the columns of pinholes in the circuitboard are what share the current and the rows all consist of independent pinholes (not sharing the current). Knowing this I basically set it up such that the components were all in one column, thinking the current would flow from the battery to the fixed resistor, then through the variable resistor then the ammeter then into the leads of the Laser (which isn't pictured) but it appears that doesn't quite work. Unless perhaps the very top two rows (where I placed the leads from the battery) are independent of the other "block" of pinholes underneath it and thus the current from the battery never reached the rest of the circuit? In this case though I notice then that I won't have enough space in one of those "blocks" on pinholes and so I wouldn't have the space to test out my circuit. There must be a way around this, if this is the case, It's just not dawning on me. Any help is GREATLY appreciated!