astronomerroyal
New Member
Hi Drew, it's email Tom.
The '2k trimpot' is a variable resistor that can go from about 0 Ohms up to 2000 Ohms. The 'trim' means that it's usually used to calibrate your circuit once and then to be left alone (and resides on the circuit board, thereafter unseen by the user.) The 'pot' is short for potentiometer, which is just a type of variable resistor you turn i.e a knob. For example, the volume control on a radio is just a potentiometer. Almost all knobs you turn are potentiometers. Do a google image search for the various things mentioned and you'll get the idea.
As for the LM317, you already know that the output voltage is determined by the resistors used.
The LM317 is ubiquitous, but you can get regulators that give a predetermined output and thus need no external components. For example the popular regulators LM7805, LM7809, LM7812 etc. will output 5, 9, 12 volts respectively. You see the naming convention.
Look at this online LM317 calculator,
**broken link removed**
If you want to be spot on then simply use your 220Ohm resistor as the first resistor and the trimpot as suggested (small variable resistor) instead of a fixed value second resistor. Using your voltmeter, turn the trimpot until you get your desired output voltage.
Also the camera probably has its own voltage regulation, so you don't have to be spot on. Batteries aren't.
I was going to do something similar (though not month-long) time-lapse. Never followed up on it, but just realised my Canon TC-80N3 Timer remote controller already does never-ending intervalometry. Are you going to use Nikon's equivalent? Anyway, regarding the power, I think you're wise to not go via the AC inverter route.
The '2k trimpot' is a variable resistor that can go from about 0 Ohms up to 2000 Ohms. The 'trim' means that it's usually used to calibrate your circuit once and then to be left alone (and resides on the circuit board, thereafter unseen by the user.) The 'pot' is short for potentiometer, which is just a type of variable resistor you turn i.e a knob. For example, the volume control on a radio is just a potentiometer. Almost all knobs you turn are potentiometers. Do a google image search for the various things mentioned and you'll get the idea.
As for the LM317, you already know that the output voltage is determined by the resistors used.
The LM317 is ubiquitous, but you can get regulators that give a predetermined output and thus need no external components. For example the popular regulators LM7805, LM7809, LM7812 etc. will output 5, 9, 12 volts respectively. You see the naming convention.
Look at this online LM317 calculator,
**broken link removed**
If you want to be spot on then simply use your 220Ohm resistor as the first resistor and the trimpot as suggested (small variable resistor) instead of a fixed value second resistor. Using your voltmeter, turn the trimpot until you get your desired output voltage.
Also the camera probably has its own voltage regulation, so you don't have to be spot on. Batteries aren't.
I was going to do something similar (though not month-long) time-lapse. Never followed up on it, but just realised my Canon TC-80N3 Timer remote controller already does never-ending intervalometry. Are you going to use Nikon's equivalent? Anyway, regarding the power, I think you're wise to not go via the AC inverter route.