Recent content by Asymptotic

This monitor isn't the one picture in earlier posts #45 and #49. If this Keweisi is the one you have https://www.amazon.com/dp/B06X6K7NK9/?tag=pfamazon01-20 it lists specifications of: . Input voltage : 3.0 - 9.0V . Measuring current: 0.00 -3.00a Unloaded, the Jameco supply voltage will be...

Make a sketch of what you intend to do. If I'm following what you are saying I think the answer is no.

You are measuring 0.49 amps at 4.96V from the powerbank, and 9.1V at 267 mA output from the 5-9V boost converter to the Dylos load. 4.96V*0.49A = 2.43 watts 9.1V*0.267A = 2.42 watts These power values agree to approximately 0.5%.

You probably want to start another thread to discuss the inner workings of air particle testers. It strays far afield of the original subject of this one ("9V 0.5A battery pack"). I'd be in the same boat as you regarding answers on this question. The sum total of what I know about them was...

The powerbank probably hides direct battery voltage information in favor of a discharge status percentage. It is a DC-DC converter built around a battery, for instance, a 3.7V Li-Ion, and a specialized chip designed to correctly charge the battery and provide a regulated output voltage when in...

Given the age and possibly storage in a non-ideal environment, one thing to check before attempting major surgery is whether there is any corrosion, burrs, dried out lubricant, and/or dirt build-up at any of the pivot points, and sliding contact points in the mechanism. If so, it may be...

The meter leads are reversed, and account for your negative current reading. The (+) ammeter lead should be connected to the (-) lead from the battery pack, and (-) ammeter lead connected to the load.

My Maglight (LED version) has a sharp cutoff between low (yet acceptable) light output to completely off when the batteries are low. Computers do bad things when supply voltages are low; exactly what these bad things are depends upon the computer, but include memory corruption, locking up...

Within limits, yes. Provided that load power is constant (and speed setpoint isn't pegged at 100%), a DC motor drive in speed feedback will draw more line current as line voltage is reduced, and visa versa. No devices where line current remains constant as line voltage varies are coming to mind...

The only way to know for certain is to measure the two quantities of interest - voltage and current - and observe how they behave. That said, I'd expect current to fall off as voltage decreases, and hence power as well. Do you know anyone who has a variable voltage DC supply? If I had a gizmo...

Yes, the ammeter leads must have been reversed. No, it won't change the value from 270 mA. Cell voltage is in large part determined by materials used for the electrodes and electrolyte, and SoC (State of Charge; how charged it is). Regarding nomenclature, although it is common practice to call...

Read about battery tech at the Battery University. This article delves into battery run-time. Pay attention to the differences between low current draw and high current draw devices. https://batteryuniversity.com/learn/article/bu_503_how_to_calculate_battery_runtime 270 mA at 6.84V is 1.85...

"Perspective" was the first word that came to mind (at least, to my mind) that conveyed the essence of "Rth across R3". Perspective, in the sense of "the combination of me, and all those connected to me". By that definition, network resistance from the perspective of R1 is 700.75Ω, from R3 is...

I believe Tom has it nailed. Recently another poster had a question involving a 9V, 500 mA transformer-based unregulated DC supply so I have the specs for that on hand. It has a transformer, full wave bridge, and 1000 uF smoothing capacitor, and in that case delivers 9 VDC at 500 mA load with...

1. This looks like a homework question. It ought to be posted in that forum. 2. Is your simplification from the perspective of R3? When I calculate the resistive network from the perspective of R3 it works out to 1.161K