This frequency/voltage converter enables calibrations of cassette-deck speed. It records a steady 1-kHz ton..

The proliferation of industrial and computerized equipment containing programmable memory has increased the need for reliable recording media. The magnetic tape medium is presently one of the most widely used methods. The primary component of any magnetic....

Many countries have 115 volts mains supplies. This can be a problem if your electric shaver is designed for 220/240 volts only. This simple rectifier voltage doubler enables motor driven 240 volt shavers to be operated at full speed from a 115 volt supply.....

This preamplifier provides proper loading ratio of better than - 70 dB (referenced to 10 to a reluctance phono cartridge. It provides mV input at 1 kHz) and has a dynamic range of approximately 35 dB of gain at 1 kHz (2 mV 84 dB (referenced to 1 kHz). The....

Door open alarms are used chiefly in automotive, industrial, and appliance applications. This type of circuit can sense the opening of a refrigerator door. When the door opens, a triac could be activated to control the inside light. The figure shows a door....

By varying either Rl or R2, the oscillator frequency can be adjusted over a narrow range. The R3/R4 ratio sets the second amplifier's gain to compensate for signal attenuation occurring in the phase shifters. The circuits can be driven from an external....

This circuit controls the level of a tank using a bang-bang controlled electrical pump. The actual level of liquid is measured by a capacitive level-meter. The first inverter performs as a capacitance to frequency converter. It is a Schmitt oscillator and....

Using a Motorola MC2833 one-chip FM transmitter, a few support components, and an MPF6660 FET RF amp, this transmitter delivers about 3 W into a 50- load...

The circuit shown here can be used to control the speed and direction of rotation of a series-wound dc motor. Silicon controlled rectifiers Q1-Q4, which are connected in a bridge arrangement, are triggered in diagonal pairs. Which pair is turned on is....

The tachometer, on the same shaft as the dc motor, is simply a generator. It gives a dc output voltage proportional to the speed of the motor. A summing amplifier, Al, controls its output so that the tachometer voltage equals the input voltage, but of....

The use of power MOSFETs allows a direct interface between logic and motor power, which permits circuit simplicity as well as high efficiency. This speed control circuit can be packaged on a 22-pin, double-sided, 3.5 4-in. pc board. A 12 V control supply....

This circuit is particularly applicable to digitally-controlled systems in robotic and X-Y positioning applications. By functioning from the 5-V logic supply, it eliminates additional motor-drive supplies. The tachless feedback saves additional space and....

The circuit uses a Hall-effect sensor, which consists of an IC that resides in a small gap in a flux-collector ..

Circuit for applying a dc-coupled FM or PPM to a 555 configured as an oscillator. IC-1 - Motorola MC-1374P. IC-2 - National LH0002C. L1, L2 - Mouser Electronics #421IF200. C1. C2 - Silver mica, 300 pF. All 0.1 uF cap., ceramic disc, 16V. C3 - 100 uF, 10 V,....

The system utilizes the H21A1 and a chopper disc to provide superior speed regulation when the dynamic characteristics of the motor system and the feedback system are matched to provide stability. The tachometer feedback system illustrated was designed....

Stepping motors find wide use in disk drives and machine control. MOSPOWER transistors are ideal motor drivers because of their freedom from second breakdown. Note that snubbing networks are not used because load line shaping is not necessary with MOSPOWER....

The circuit is light seeking; it will follow a flashlight around a darkened room. A pair of photocells determine the direction in which the robot will move. Each photocell is connected to an op amp configured as a comparator. When sufficient light falls on....

The circuit uses a 4011 CMOS NAND gate, a pair of diodes and an NPN power transistor to provide a variable duty-cycle dc source. Adjusting the speed control varies the average voltage applied to the motor. The peak voltage, however, is not changed. This....

Using a Motorola MC34118 speakerphone IC, this adapter can be used with a regular telephone to provide speaker capability. This device is powered from the phone line, but it can be powered via an external power supply if the line loop current is marginally....

Industrial applications sometimes require that power be only briefly applied to a load following the closure of a switch, such as a microswitch or foot switch. The load could be a heating element for use in sealing plastic bags, a de motor that is indexed....

Half of a Motorola MG14538B dual, precision, retriggerable mono stable multivibrator is used to form an extended on-time timer circuit. That type of circuit can be used as a switch debouncer. Such circuits are often used in digital circuitry, where each and....

The circuit illustrates feedback speed regulation of a standard ac induction motor, a function difficult to accomplish other than with a costly, generator type, precision tachometer. When the apertured disc attached to the motor shaft allows the light beam....

This circuit operates like the one shown in Fig, 57-4, The only differences are that the field is placed across the rectified supply and the armature is placed in the SCR bridge. Thus the field current is unidirectionali)ut armature current is reversible;....

Power op amps provide accurate speed control for dc motors. The circuit provides bidirectional speed control. The amplifiers' push-pull configuration ensures a full rail-to-rail voltage swing (minus the output stages' saturation drops) across the motor in....

Choosing de rather than ac coupling can reduce much of the noise associated with preamplifiers for a magnetic reading head, particularly in the low frequencies. The LM1897 eliminates the need for the capacitor that usually ac couples the read head to the....

Many record players unfortunately exhibit two undesired side effects: rumble (noise caused by the motor and the turntable) and other low-frequency spurious signals. The active high-pass Chebyshev filter presented here was designed to suppress those noises.....

A transducer senses a direct current magnetically, providing isolation between the input and the output. The detecting-and-isolating element is a saturable reactor, in which the input current, to be measured, passes through a one-tum control coil. The....

In operation, the TL3019 device will activate, or become low, when a south pole of a magnet comes near the chip face of the device. The example shows five doors. Each door has a magnet embedded in its edge with the south pole facing the outer surface. At....

When used in the servo system, often using the current drive connection. Figure 11-1, the output current IOUT and the input channel number y.. It is proportional. Current drive mode can be reduced because the motor has a large inductance causes a phase....

Adopt and put the intermodal servo preamplifier circuit as shown, the circuit is 115V, 60Hz servo motor amplifier provides a differential output. An op amp inverting connection..

As shown for the OPA37 constitute a low-noise preamplifier. Input signal is applied OPA37-inverting input (pin 3), circuit RL, CL is the load impedance electromagnetic pickups,..

Circuit shown in Figure 3-10. This is a multi-function input with a preamplifier, including the tuner input, a magnetic tape playback input, magnetic phono input and phono equa..