Voltage Spike for Solenoids

Archiver

Hey Everybody!

I am fairly new to electronic circuits so bare with me. :-) I would
like to supply a quick voltage spike to a solenoid in order to
actuate it with a stronger force. From what I have been reading, I
think that a capacitor will do this, however I do not have any idea
how to actually make it happen (i.e. code, schematic, ect.) By the
way, I have a Darlington transistor array between the solenoid and
the stamp to take care of the current issues, and I am using a BS2SX
and a simple Guardian push type solenoid. Can anyone please help me
with this setup? I want to make sure I do this right so as to not
damage any of the components. Thanks!

Jason Schuler

Archiver

Hey Everybody!

I am fairly new to electronic circuits so bare with me. :-) I would
like to supply a quick voltage spike to a solenoid in order to
actuate it with a stronger force. From what I have been reading, I
think that a capacitor will do this, however I do not have any idea
how to actually make it happen (i.e. code, schematic, ect.) By the
way, I have a Darlington transistor array between the solenoid and
the stamp to take care of the current issues, and I am using a BS2SX
and a simple Guardian push type solenoid. Can anyone please help me
with this setup? I want to make sure I do this right so as to not
damage any of the components. Thanks!

Jason Schuler

Archiver

On the old-style pinball machines, they have a switch attached to the
flipper that is used to reduce the voltage to the coil once the solenoid
plunger is at full travel -- this is one way to do it.

The capacitor idea may or may not work depending on if the power source
itself is not able to deliver enough current to the coil when its fired. If
the power supply is adequate this method probably won't work.

On idea might be a 2-stage power source -- power the coil with a higher
voltage to get it moving, then switch to the normal coil voltage to keep it
moving. You would have to be careful not to supply the higher voltage too
long though -- it may burn out the coil. Might try doing a search to see if
you can find anything similar.

---

Original Message

---

> I am fairly new to electronic circuits so bare with me. :-) I would
> like to supply a quick voltage spike to a solenoid in order to
> actuate it with a stronger force. From what I have been reading, I
> think that a capacitor will do this, however I do not have any idea
> how to actually make it happen (i.e. code, schematic, ect.) By the
> way, I have a Darlington transistor array between the solenoid and
> the stamp to take care of the current issues, and I am using a BS2SX
> and a simple Guardian push type solenoid. Can anyone please help me
> with this setup? I want to make sure I do this right so as to not
> damage any of the components. Thanks!

Archiver

A typical solenoid will hold in with about 1/4 of the current required to
pull it in initially. I've done this by putting a resistor in series with
the solenoid to limit the current to about 1/4 of the rated current, then
have a field-effect transistor across the resistor. There is a capacitor
and resistor in the gate circuit of the FET so that when the capacitor
discharges, the FET which was originally conducting and shorting out the
resistor, cuts off and allows the resistor to be back in the circuit.

With a Stamp, you could just have a transistor across the resistor, and
drive it from a Stamp pin, doing the timing in the stamp. Start off with
the pin driving the transistor high to short out the resistor. Allow say
1/2 of a second for pullin, then turn off the transistor by setting the
pin low.

Larry




At 12:48 AM 12/12/2002 +0000, you wrote:
>Hey Everybody!
>
>I am fairly new to electronic circuits so bare with me. :-) I would
>like to supply a quick voltage spike to a solenoid in order to
>actuate it with a stronger force. From what I have been reading, I
>think that a capacitor will do this, however I do not have any idea
>how to actually make it happen (i.e. code, schematic, ect.) By the
>way, I have a Darlington transistor array between the solenoid and
>the stamp to take care of the current issues, and I am using a BS2SX
>and a simple Guardian push type solenoid. Can anyone please help me
>with this setup? I want to make sure I do this right so as to not
>damage any of the components. Thanks!
>
>Jason Schuler
>
>
>
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Larry Bradley
Orleans (Ottawa), Ontario, CANADA

Archiver

At 08:00 12/12/02, Larry Bradley wrote:
>A typical solenoid will hold in with about 1/4 of the current required to
>pull it in initially. I've done this by putting a resistor in series with
>the solenoid to limit the current to about 1/4 of the rated current, then
>have a field-effect transistor across the resistor. There is a capacitor
>and resistor in the gate circuit of the FET so that when the capacitor
>discharges, the FET which was originally conducting and shorting out the
>resistor, cuts off and allows the resistor to be back in the circuit.
>
>With a Stamp, you could just have a transistor across the resistor, and
>drive it from a Stamp pin, doing the timing in the stamp. Start off with
>the pin driving the transistor high to short out the resistor. Allow say
>1/2 of a second for pullin, then turn off the transistor by setting the
>pin low.

The approach I've used successfully with DC solenoids is to determine the
rated coil current and voltage, then fire the coil with several times that
voltage, but with a resistor in series to limit the current to the coil
rating. This produces faster actuation, but does not exceed the coil
current rating. I'm assuming the coil can remain activated for the desired
time at its full rated current without problems.

Jim H