How do you connect a 12V DC solenoid to a 24V DC circuit?
- Thanks again for the good advice. I don't think a resistor is needed in this application. When the devices are turned off, the devices will remain off for at least three seconds.
--- In Electronics_101@yahoogroups.com, "Kerim F" <ahumanbeing2000@...> wrote:
> I like adding a small remark. When I switch a relay 12V (or 24V) coil using a transistor with Vceo > 30V (or 60V) and the relay off response should be `relatively' fast, I add a resistor in series with the reversed diode having a value about the coil's one (or a bit less). In this case, the applied 'transient' voltage at turn off will be about 2*Vcc but the coil energy will also discharge much faster (ratio about Vcc/0.7).
> --- In Electronics_101@yahoogroups.com, "Andrew Mathison \(Alice\)" <mathison@> wrote:
> > You are correct, always place a reversed diode across any coil that is being
> > switched on and off with DC voltage.....the so called "Back E.M.F." can be
> > many times larger than the original voltage source, that's how a car's
> > ignition system makes high voltage for the spark plugs from 12 VDC.
> > Regards
> > Andy