Driving loads with MP3 player

Started by Bob Kindle in sci.electronics.design10 years ago 4 replies

I would like to use a pocket-size MP3 player to feed audio signals direct (no added amp) to a solenoid type coil. The coil resistance itself...

I would like to use a pocket-size MP3 player to feed audio signals direct (no added amp) to a solenoid type coil. The coil resistance itself would be negligible. What is the minimum series resistance required to avoid overloading the player's output? I am thinking maybe 32R? Any suggestions? Bob Kindle


arc suppressor for relays

Started by Jon Elson in sci.electronics.design9 years ago 36 replies

We have one of those $1K high efficiency washing machines. It does work, and clearly reduced our water and gas bill, so I'm not...

We have one of those $1K high efficiency washing machines. It does work, and clearly reduced our water and gas bill, so I'm not complaining. Lately, it has been getting "slow fill" errors, and I tried a bunch of typical stuff before finding the REAL problem. They have a bank of electromechanical relays to operate a bank of solenoid water valves. There is no arc suppression on these relays,...


Coil electrodynamics

Started by Karl Roberts in sci.electronics.design10 years ago 21 replies

Can anyone please clarify the following for me? Two part question: If I take a solenoid and feed a positive DC offset sinewave (ie. 6V max...

Can anyone please clarify the following for me? Two part question: If I take a solenoid and feed a positive DC offset sinewave (ie. 6V max 2V min) into one end and an inverted copy with a similar negative offset (ie -2V max -6V min) into the opposite, what, in terms of electrodynamics, occurs within the coil? If I now split the coil in half and ground the center point, what happens no...


Delay in 3 meters of wire

Started by amdx in sci.electronics.design8 years ago 20 replies

Hi Guys, I have question about transit time in a wire and phase shift caused by inductance. I'm going to use 3 meters of wire and...

Hi Guys, I have question about transit time in a wire and phase shift caused by inductance. I'm going to use 3 meters of wire and 300,000,000m/s (discuss speed later) 300,000,000m/3m =10 nanoseconds, What travels? Will I measure both current and voltage as having a 10 ns delay at the other end of the wire? Now, I wind the 3 meters of wire as a solenoid coil and I have a 30 uh co...