I posted this comment to FB Arduino group 2017-09-22. “Can I use a 7805 (regulator IC) to charge my cell phone?” The output is 5 volts, which is what the phone needs to charge. But the average smart phone will take more than 1 amp, up to 2 amps to charge quickly. The 7805 can’t
(Read More…)
My answer to a FB Arduino group question on Sept 17 Dan Rogers has the right idea. The protoboard, with all the holes in it, was never meant to be permanent. The contacts in each hole lose their springiness as they are used to hold wires. The contacts can become intermittent after awhile. As time
(Read More…)
From a FB group post. “primitive transistors” I think that’s ironic. The 555 makes the design easier for the builder. It has all the parts so the builder doesn’t have to build from scratch. Like making a cake using Betty Crocker’s cake mix instead of flour, eggs, etc, and no need for a recipe. It’s
(Read More…)
From my FB comment Some comments say measure with a meter, but fractional ohm resistors don’t measure, or barely measure with the typical ohmmeter. Instead, you should be giving better advice. You should use the device between your ears to find the resistance. The resistor should be put in series with another resistor of
(Read More…)
From YT reply to Neilgn 2017-08-20 Take any NPN transistor and measure the gain, and write it down. Then put a 1k resistor in series with the transistor’s emitter and connect the emitter to positive and base to negative of a power supply. Adjust the voltage until 2 or 3 volts are across the 1k
(Read More…)
From FB comment There are many factors that affect price. One part is getting things assembled by underpaid and child (illegal) labor. Most discounters have been caught buying their goods from these illegal sweatshops, and they still turn a blind eye to these abuses. The net result is that the quality of the components may
(Read More…)
From FB post One important thing that people forget to do is consider what might happen with a circuit that has anything that draws power from the protoboard. If you’re working with a few low power devices such as small LEDs and switches, then there is usually not a problem. But if you have a
(Read More…)
From FB reply My remotes seem to go bad all the time. Batteries low or dead, battery juice leaking on the circuit board, broken wires from falling off the table, getting sticky or worn, etc. I try to minimize the wear and tear on the original remote. I never use the original remote, I use a cheap
(Read More…)
I bought several of these miniature audio transformers from Electronic Goldmine. They are encapsulated so I can’t see anything, windings, core or materials. There are 5 pins, 2 on one side and 3 on the other, but the center pin measured open, so it’s apparently there to make sure the transformer is inserted the right way. The
(Read More…)
