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Control circuit for solenoid valve

  • US 5,632,468 A
  • Filed: 02/24/1993
  • Issued: 05/27/1997
  • Est. Priority Date: 02/24/1993
  • Status: Expired due to Fees
First Claim
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1. A solenoid valve, comprising:

  • a valve adapted to move between a first position and a second position;

    a solenoid that moves said valve from said first position to said second position when a first voltage is applied to said solenoid, and maintains said valve in said second position when a second voltage is applied to said solenoid, wherein said first voltage is greater than said second voltage;

    a solenoid circuit that initially applies said first voltage to said solenoid to move said valve to said second position and then subsequently applies said second voltage to said solenoid to maintain said valve in said second position, said second voltage being applied to said solenoid a predetermined time interval after application of said first voltage to said solenoid, said solenoid circuit contains a Voltage divider circuit connected to said solenoid, a transistor connected to said voltage divider circuit and said solenoid, a capacitor connected to said transistor, and a single source of power connected to said voltage divider circuit, said transistor and said capacitor, such that said capacitor is initially charged and said transistor is in an active state so that current from the power source by-passes said voltage divider and said first voltage is applied to said solenoid, and said capacitor becomes charged and said transistor is in an inactive state to allow current to flow through said voltage divider circuit so that said second voltage is applied to said solenoid, wherein said predetermined time interval is dependent on a time constant of said capacitor.

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