This circuit monitors the power-line (ac) voltage. When a power failure occurs, on restoration of power, the circuit a..
The PWM controller uses complementary half-H peripheral drivers SN75603 and SN75604, with totem-pole outputs rated at 40 V and 2.0 A. These drivers effectively place the motor in a full-bridge configuration, which has the ability to provide bidirectional control. Timer U1 operates in the astable mode at a frequency of 80Hz. The 100-0 discharge resistor results in an 8-p.s trigger pulse which is coupled to the trigger input of timer U2. Timer U2 serves as the PWM.....
The controller circuit can reduce a fan"s noise, power consumption, and wear, particularly in the presence of a low, fluctuating ambient temperature. Mount a temperature sensor in the fan"s airstream, and the circuit will adjust the fan speed as necessary to maintain a relatively constant sensor temperature. Input components Rl and Cl integrate the input square wave, producing a quasitriangular wave at the noninverting input of op amp IC1A. At this inverting input is a.....
In this proximity detector an NE567 tone decoder provides a signal of about 100 kHz that is fed to one sensor. The senso..
Dc power can also be controlled via fiberoptics. The circuit provides an insulated speed control path for a small dc actuator motor (< Vn hp). Control logic is a self-contained module requiring about 300 mW at 12 V, which can be battery powered. The control module furnishes infrared pulses, at a rate of 160 Hz, with a duty cycle determined by the position of the speed adjust potentiometer. The programmable unijunction multivibrator provides approximately 10 mA pulses to.....
The resistor capacitor network R1-R2-C1 provides a ramp-type reference voltage superimposed on top of a dc voltage adjustable with the speed-setting potentiometer R2. This reference voltage appearing at the wiper of R2 is balanced against the residual counter emf of the motor through the SCR gate. As the motor slows down due to heavy loading, its counter emf falls, and the reference ramp triggers the SCR earlier in the ac cycle..
The modified power-factor controller, developed at the Marshall Space Flight Center, employs a phase detector for each of the three phase windings of a delta-connected induction motor. The phase-difference sum is the basis for control.
The control of both direction and of proportional motor speed is achieved by rotation of a single potentiometer. The motor driver is an SGS integrated circuit L293 which will drive up to 1 amp in either direction, depending on the logic state of input 1 and input 2 as per table. I/P 1 I/P 2 Function. High Low Motor turns one way. Low High Motor reverses. By applying a variable M/S ratio flip-flop to these inputs, both speed and direction will be controlled. With RV1 in its.....
This single time-constant circuit can be used as proportional speed control for induction motors such as shaded pole or permanent split-capacitor motors when the load is fixed..
This circuit is intended as a revolution control for small dc motors as fitted, for instance, in small electric drills (..
The system shown consists of the HA-2542, a small 12-Vdc motor, and a position encoder. During operation, the encode..
The NE5561 provides pulse-proportional drive and speed control based on de tachometer feedback. This simple switching circuit consists of transistor 2N4920 pnp with a commutation diode used to deliver programmed pulse energy to the motor. A frequency of approximately 20 kHz is used to eliminate audio noise. The de tach delivers 2.7 V/1000 RPM. Negative feedback occurs when this voltage is applied to the error amplifier of the NE5561. ..
Universal motors and shade d-pole induction motors can be easily controlled with a full-wave Triac speed controller. Q1 combines both the triac and diac trigger diodes in the same case. The motor used for the load must be limited to 6 amperes maximum. Triac Ql must be provided with a heat sink..
This is a positioning servo drive featuring adjustment of balance, gain, and deadband. In addition to control from a dc signal, mechanical input can be fed into the balance control, or that control could be replaced by a pair of resistance transducers for control by light or by temperature.
Most standard household appliances and portable hand tools can be adapted to variable -speed operation by use of this simple half-wave SCR phase control. It can be used as the speed control unit for the following typical loads pro-videe they use series universal (brush type) motors. During the positive half cycle of the supply voltage, the arm on potentiometer R2 taps off a traction of the sine wave supply voltage and compares it with the counter emf of the motor through.....
This electronic motor-speed control circuit is designed to operate in an electrically noisy environment. The circuit includes an optoelectronic pickup device. whichis placed inside the motor housing to provide a speed feedback signal. The circuit automatically maintains the speed of the motor at the commanded value. The pickup device contains an infrared LED and a phototransistor. The radiation from the diode is chopped into pulses by the motor fan blades. which are.....
When the time delay expires, SCRl conducts and removes the gate signal from SCR2, which stops the motor. Both the time delay and motor speed are adjustable by potentiometers R2 and R3. If heavier motor loads are anticipated, use the larger C30B SCR in place of the GE-X1 for SCR2..
Because of its high amplification factor and built-in power-output stage, an integrated power operational amplifier makes a convenient driver for ac motors. One op amp can be configured as an oscillator to generate the required ac signal. The power-output stage, of course, supplies the high-current drive to the motor.
This circuit is intended for use with motors, lamps,heatings etc. Continuously from nearly zero up to maximum capacity (5-95%). Almost lossfree control by means of this impulse control. Nearly total turning moment of motors. The transistior T3 must absolutely be fastened on a heatsink with minimum dimentions of approximate 100x100x5mm. The heatsink has to be fixed insulated as the transistor has a conductive connection between the C-connection and the metal rear side...
This high-performance switching controller for a low-power de servo motor uses a symmetrical complementary- transistor bridge. The bridge acts as a reversing switch between the motor and a single-ended power supply. Since the transistors operate either fully on or completely off, except during a very short transition period, much less heat is dissipated than in linear-amplifier circuits. Damping is provided by the circuit"s inherent dynamic braking. ..
Transmitters & Receivers
Sensors & Detectors
Low Frequency Amplifiers
Regulated Power Supplies