Re: Laser Barrels V2. GB. Second run. Kryton Groov
Voltage drop will vary with current draw, which for the Lavadrive will vary depending on the output current setting and the input voltage (higher input than output voltage means lower input than output current and vice versa).
Also, you will want to make sure the power handling of the resistors is enough to handle however much power the resistors are dissipating.
Can calculate as P = I^2 * R or P=V^2 / R or P = V * I
You can calculate the resistance you need for a voltage drop at a given current just by using Ohm's Law (2.9V drop at 150mA with fresh charged batteries putting out 8.4V lavadrive voltage output ~= input, for 803T), but remember the Lavadrive is a step up/down circuit and the input current will vary with voltage, as mentioned previously:
V= I * R
2.9V = 0.150A * Rx
Rx = 2.9V /0.150A
Rx = 19.3ohm or ~20ohm
You're likely getting the drop you are at ~600kohm because the multimeter is acting as the load and draws VERY little current.