Strange LO Oscillator won't oscillate

Started by Bill Bowden in sci.electronics.basics5 years ago 4 replies

It's a Autodyne converter in a small AM Radio. DC voltages look ok but doesn't oscillate. Originally, the problem was a weak transistor with a...

It's a Autodyne converter in a small AM Radio. DC voltages look ok but doesn't oscillate. Originally, the problem was a weak transistor with a hFE of 4. I replaced the tranny with a 2N2222A and it worked fine for a couple weeks and then died. Now the DC voltages look ok with about 1.5 volts on the emitter. Usually, this type of oscillator has the coil tap connected to the emitter throu...


Major Differences In Small Engine Coils

Started by Bret Cahill in sci.electronics.basics8 years ago 7 replies

Maybe the voltages vary somewhat for different point and plug gaps but is it enough to make any difference? . Supposedly Honda no longer...

Maybe the voltages vary somewhat for different point and plug gaps but is it enough to make any difference? . Supposedly Honda no longer makes the coils for their 100 outboard, a 2 cylinder 4 stroke engine. Isn't it likely that other small engines, say from riding lawnmowers, use coils that are pretty much the same? For that matter couldn't a motor vehicle coil work? Bret Cahill ...


Permeability in a DC Motor

Started by Anonymous in sci.electronics.basics4 years ago 15 replies

Two motors were evaluated to find the ratio of the speed of the rotor over the speed of the electron in the coil. ratio = speed(rotor) /...

Two motors were evaluated to find the ratio of the speed of the rotor over the speed of the electron in the coil. ratio = speed(rotor) / speed(electron) ratio = 8 meters per second / 10 microns per second Some calculations show that DC electric motors rotate thousands of times faster than the electrons move in the drive current. For example, the Mabuchi RE 280RA motor has a c