Hmm, the picaxe output goes to a transistor (on the relay board) that
sends the 12V unregulated voltage to the relay.
Have you used diodes between the collector of the transistor and the
relay terminal(cathode towards collector)?
Otherwise the back current when the relay changes from on to off may
be causing the problem.
simulation yields negative current.wierd!! ...transistor, 12 volt battery via a relay to the collector and ground to ... resistor to base n collector.... (sci.electronics.design)
Re: BC857 Destroyed - Schematic ...peak collector current is over 100mA with only 2mA of base drive? ... There are single diodes in the same package ... If the BAV70s on failed units have ... It might be worthwhile to hang a fast digital scope on TR8's collector and trigger that with a relay command.... (sci.electronics.design)
Re: The KenSmith Jinx ... Energize the relay when you turn on your ... and through another series diode and resistor to the base of a PNP ... Connect the emitters of the transistors together and to ... Connect the collector of the NPN to V+ and the ... (sci.electronics.design)
Re: 74LS05 driving Relay ... >the collector to the side of the relay that would be grounded, ...>transistor,... >energy when its off, so put a damper diode across the NPN collector/emitter,... >then connect the relay - side to the collector,... (sci.electronics.design)
Re: Will the LM393 drive a small relay? ... trigger this relay?... I would add a driver transistor with a clamp diode across the coil.... If you can reverse the sense of the comparator all you need is to connect an NPN transistor like a 2N3904 or 2N4401 emitter to ground, base to comparator output, collector to coil, other end of coil to +5, 1k resistor base to +5. ... (sci.electronics.basics)
