Showing papers on "Decoupling capacitor published in 1968"

Stabilizing phase controlled ac induction motors

Abstract: An adjustable speed capacitor run or polyphase AC induction motor energized by phase controlled voltage is stabilized by an AC phase control circuit whose timing is referenced to the zero crossing of the capacitor voltage in an RC circuit and supplies gating signals to a thyristor in series with the motor, characterized by a degenerative feedback circuit comprising an impedance element connected to modify the capacitor voltage in such manner that the cessation of thyristor conduction modulates the timing of the next gating signal.

Capacitor discharge ignition system

Abstract: A capacitor discharge ignition system is provided with a control arrangement to prevent operation of an engine at excessive speeds. For example, when the engine exceeds a predetermined speed of operation, the control arrangement is effective to terminate the generation of the ignition firing pulses to the spark plug of the engine. The control arrangement includes a capacitor connected at one end to the cathode of an SCR switching device that controls the discharge of a charging capacitor into an ignition coil. The other end of the capacitor is connected in the triggering circuit of the SCR. The capacitor discharge ignition system is arranged to charge the charging capacitor during a first half cycle of operation of one polarity and subsequently to discharge the capacitor into the ignition coil by triggering the SCR during the following half cycle of operation of opposite polarity. The charging of the capacitor and the triggering of the SCR are controlled by voltage and current waveforms generated by a control winding that is disposed on a ferromagnetic core. The ferromagnetic core is positioned adjacent the rotating magnetic field that is developed for example by a permanent magnet carried by the flywheel of the engine.

Triggered ignition system

Abstract: This disclosure relates to an alternator-driven capacitor system for a two-cylinder engine. A main capacitor is connected across the output of the alternator. Separate discharge circuits for each of the spark plugs are connected in parallel to the capacitor and each includes a silicon-controlled rectifier and a pulse transformer. A trigger capacitor in series with a resistor is connected across the main capacitor. Paralleled trigger circuits are connected to the trigger capacitor and each includes a pulse transformer in series with a silicon-controlled rectifier. The pulse transformers are connected to fire a corresponding main-controlled rectifier. The controlled rectifiers of the trigger circuits are fired from a separate pulse generator driven in synchronism with the engine.

Control circuits for electromagnetic clutch-brake driving devices

Abstract: A circuit which does not require mechanical relays is disclosed using silicon-controlled rectifiers (SCR''s) for controlling manually and/or automatically the starting and stopping of a clutch-brake motor having an electromagnetically actuated clutch and brake. Each clutch turnoff brake winding is connected to a source of full wave rectified AC voltage through its own SCR and selective turnoff is effected by capacitor commutation. Momentary overexcitation of both windings is provided by alternative initial discharge therethrough of energy previously stored in respective capacitors. These capacitors are charged through separate individual SCR''s from an AC voltage of a value higher than the normal DC energizing voltage used for continuously exciting the coils. The four SCR''s are turned on in pairs, one SCR of each pair closes a circuit connecting the respective winding to the previously charged capacitor and thereafter to the normal DC energizing bus. Diode gates prevent adverse interaction between the capacitors and the DC bus and provide properly timed energy flow from the DC bus to the winding as soon as the capacitor voltage drops to a value slightly below the bus voltage so that there is no discontinuity in the winding excitation. The trigger pulse which turns on one SCR to energize one winding also turns on the other SCR of the pair, which latter SCR connects the capacitor for charging or storing energy which is later released for initially energizing the other winding. A no-voltage release circuit employs a unijunction transistor (UJT) as a relaxation oscillator connected to a DC supply having a large capacitor. This oscillator provides triggering pulses to the gate of the SCR which controls excitation of the brake winding. Normally, however, with full line voltage, a transistor base-biased to saturation, has its emitter-collector circuit connected across the timing capacitor of the UJT oscillator, thus normally shorting the capacitor and preventing oscillation. Upon failure of line voltage, the transistor turns off due to loss of base bias and the timing capacitor charges from the energy in the large capacitor, and the oscillator supplies a triggering pulse to the SCR for energizing the brake coil. The voltage of the previously charged capacitor now connected to the brake winding will, even in the absence of line voltage, supply a high impulse of energy to the brake coil to bring the load quickly to standstill.

High voltage power supply for a flash discharge lamp

Abstract: A power supply for a flash discharge lamp includes a capacitor and a voltage divider in parallel. A gas discharge tube is in parallel with a first part of the voltage divider and a controlled switching element is in parallel with a second part thereof. The gas tube is connected to the switching element so that at a given voltage across the capacitor, the gas tube ignites and causes the switching element to change state. This in turn abruptly alters the voltage distribution across the voltage divider in a sense to reduce the voltage across the gas tube to a level close to its operating voltage. The charge current to the capacitor is then interrupted. A relatively small discharge of the capacitor causes the gas tube to turn off, thereby allowing the capacitor charge current to flow again. The capacitor voltage variation is thus held within a narrow range.

Thermal analogue protection for capacitors

Abstract: A capacitor protection system is provided having the primary winding of a potential transformer connected across a series capacitor bank to be protected and the secondary winding of the potential transformer connected to a thermal analogue device which reproduces the thermal characteristics of the capacitor and operates capacitor switching means when dangerous thermal conditions are reached. An inverse time voltage relay is also connected across the secondary winding to initiate protective capacitor switching responsive to high current faults. The thermal analogue device simulates the internal thermal conditions of the capacitor based on the principle that the power loss in the capacitor is proportional to the square of the voltage across the capacitor. Voltage comparison circuits are also provided between groups of capacitors in banks having multiple groups to detect blown fuses associated with respective capacitor groups.

Electronic actuator and timer circuit

Abstract: A number of actuator circuits, each having a switch and a capacitor connected in series, are connected to a transformer primary winding. The transformer secondary winding is coupled to a controlled rectifier having a timer capacitor connected to its anode-cathode path. An output circuit is coupled to the timer capacitor. Closing of any one of the switches renders the controlled rectifier conductive to charge the timer capacitor, after which the controlled rectifier is turned off so as to be responsive to closing of another switch. The output circuit produces a signal as long as the timer capacitor has a charge.

Charging circuit for establishing a dc voltage level

Abstract: A desired DC voltage level is developed across a capacitor by applying a signal of a particular frequency to the capacitor through a neon tube. The voltage level stored in the capacitor is coupled to other circuitry by a field effect transistor. The capacitor, neon tube and field effect transistor are packaged in an opaque epoxy to increase the resistance of leakage paths. Clamping circuits are used to limit the range of the voltage stored in the capacitor. The input to the charging circuit is balanced for noise and unbalanced for the signal frequency to provide noise immunity. yThis application is a continuation-inpart of the application of Robert B. Hansen and Gordon E. Reichard, Ser. No. 644,301, filed Jun. 7, 1967, now abandoned.

Temporary memory restore circuit for multivibrator

Abstract: There is provided a temporary memory restore circuit for actuating a bistable multivibrator to its last stable state prior to removal of power, when power is returned to the circuit. The memory restore circuit includes a storage capacitor, which is connected across the output of the bistable multivibrator. The capacitor monitors the operation of the multivibrator and is charged in accordance with the last stable state of the multivibrator. Connected in series with the storage capacitor is a normally open circuit means for connecting the capacitor across the output circuit of the bistable multivibrator when power is applied to the circuit, and for disconnecting the capacitor from the circuit when power is removed.

Staircase voltage generators

Abstract: A multilever staircase generator employs a transformer having a core fabricated from a square loop magnetic material. The secondary winding of the transformer is shunted by a capacitor while the primary winding forms part of a controllable current loop, whose path is selected by activation of a suitable thyristor. During a first mode the secondary capacitor is charged to a stepped up, high-voltage level by causing a lower voltage to appear across the primary winding, after the activation of a first thyristor. A second mode occurs after the secondary capacitor transfers sufficient energy to saturate the secondary winding inductance and cause core switching; at which time the capacitor is charged to an opposite polarity. A third mode is provided by activating a second thyristor, which causes the secondary capacitor to transfer the energy stored thereby to a reactive impedance element located in the primary winding and switched into a suitable path by said thyristor activation.

Feedback speed control circuit for an electric motor

Abstract: A speed control circuit for a universal electric motor having series connected armature and field windings, wherein a controlled semiconductor, such as an SCR, is utilized A circuit containing a fixed resistor and a variable resistor is connected to the supply voltage The fixed resistor is connected in parallel with a capacitor and the armature windings forming a series circuit loop containing the fixed resistor, capacitor, and the armature windings wherein the back EMF generated in the armature windings affects the amount of voltage for charging the capacitor The control electrode of the semiconductor is connected by a voltage triggered signal channel to the capacitor A selected operating speed is obtained by adjustment of the variable resistor In this control circuit the capacitor is charged during the positive half-cycle by a voltage (across the fixed resistor) which is a fraction of the supply voltage minus the back voltage generated in the armature windings until the triggering voltage for the signal channel is built up on the capacitor whereupon the signal channel will be made conductive to fire the semiconductor into a conductive state Preferably a diode is connected in shunt relation with the field windings to provide controlled excitation of the field windings during the negative half-cycle so that a significant armature back voltage is generated in the armature windings

Capacitive discharge fuze

Abstract: This invention relates to a fuzing device and, more particularly, to a capacitive discharge fuze for an explosive embedment anchor. This fuze device makes use of a battery, the voltage of which is in excess of the maximum working voltage of the capacitor, to reduce the charging time to an acceptable minimum. A first switch connects the battery to the capacitor. A Zener diode acting in conjunction with a silicon controlled rectifier and a replaceable fuse element control the charging of the capacitor. At the rated voltage of the capacitor, the Zener diode triggers the silicon controlled rectifier causing a short circuit through the fuse element across the capacitor. The excessive current through the short circuit path melts and permanently opens the fuse element thereby permanently isolating the charged capacitor from the charging circuit. A second switch discharges the capacitor through a detonator.

Electronic circuit in which the operating voltage is obtained from the high voltage side of the circuit

Abstract: The circuit includes a semiconductor device coupled in series with an inductance winding and a capacitor. A second semiconductor device is coupled in series with a second capacitor and is operably coupled to the inductance winding. A DC voltage is applied across the second capacitor and a starting voltage is applied across the first capacitor. Pulses developed across the inductance winding are rectified by the second semiconductor device and coupled back to the first capacitor to provide an operating voltage for the first semiconductor device.

Capacitor type timing circuit utilizing energized voltage comparator

Abstract: There is provided a strobed timing circuit which includes a timing capacitor connected across a voltage source for charging at a predetermined rate, and a comparator circuit for providing an output signal when the voltage across the capacitor reaches a set-in value. The comparator circuit is turned on for relatively short intervals of time to measure the voltage across the capacitor to thereby provide a comparator circuit with an apparently high input impedance.

Automatic degaussing circuit for tv having half-wave voltage doubler power supply

Abstract: Automatic degaussing circuit for a color television receiver employing a half-wave voltage doubler type power supply. The series capacitance of a cascaded voltage doubler power supply is provided by a pair of capacitors in parallel current paths. A thermistor, connected in series with the capacitor of one current path, is shunted by the series combination of VDR and a degaussing coil. A second thermistor is connected in series with the capacitor of the remaining current path. Initially upon turn-on of the cold receiver, the major portion of capacitor charging current passes through the then low impedance VDR-coil path and the capacitor in series therewith, the value of this capacitor being chosen to ensure substantially symmetrical AC energization. Subsequently, after thermistor warmup, current flow is equally divided between the parallel capacitances, and the voltage doubler operates efficiently with an augmented value of series capacitance corresponding to sum of the parallel capacitances.

Capacitor charging and discharging control system

Abstract: A control system is disclosed for controlling the production of high-magnitude current pulses to a load, such as a magnetic pulse-forming work coil, at high-pulse rates by selectively charging a capacitor bank and then discharging the same through the load, the operation of the system taking place in a predetermined manner. A logic system automatically deactivates the control system in the event that the operation is other than in this predetermined manner, and antiringing circuitry eliminates ringing effects in the load circuit. A low-inductance, high-current damping resistor safely dissipates certain undesirable high-surge currents in the system to provide long component life and high-speed operation.

Digital to analog converter having capacitor charged by input code pulses

Abstract: A digital to analog converter for sequential weighted pulse groups features a capacitor coupled to a resistor ladder network. The pulses are applied to a distributor and then to a pulse circuit which charges the capacitor from different points on the network depending upon the weighted value of the pulse.

Self-biasing percussion system for an electronic organ

Abstract: A self-biasing percussive gate for an electronic organ including a relatively small capacitor C1 in series with a continuously connected tone signal source which provides positive signal pulse trains of selective frequencies, in response to playing of the organ, the small capacitor C1 being connected in a shunt path to ground which contains a first diode and a large capacitor C2, the first diode being poled to conduct in response to positive signal The anode of the first diode is connected to the cathode of a gating diode, the anode of which is connected to a load circuit A timing circuit is provided between the source and the small capacitor to smooth and control voltage changes during each pulse Means are provided for momentarily short circuiting the large capacitor, as each tone is called for by the player, an action which initiates the percussive tones Each tone persists for a time which is inversely proportional to the frequency of that tone signal, and has a progressive modification of tone color in proceeding from its initial to its final points Tone color is also a function of frequency

Exposure time control system for photographic apparatus

Abstract: Light is transmitted through the original onto photosensitive material in each of three primary colors. Three secondary electromultipliers furnish electrical currents which vary as a function of the light received by the photosensitive material in each color. Each current is integrated by a capacitor, the voltage on the capacitor compared to a reference voltage, and a relay energized when the capacitor voltage and the reference voltage have a predetermined relationship. Each relay has a first set of contacts for terminating the illumination in the corresponding color and a second set of contacts for shorting out part of a resistance connected in series between the supply voltage terminal and a transformer supplying voltage to the secondary electron multiplier corresponding to the other colors. This increases the sensitivity of the other electron multipliers, increasing the charging rate of the capacitor, and thus decreasing the exposure time in the other colors.