Circuit Diagram

Tachless_motor_speed_controller

Published:2009/7/24 23:28:00 Author:Jessie

This circuit is particularly applicable to digitally controlled systems in robotic and X-Y positioning applications. The circuit controls from 20 rpm to full speed (with good transient response under all shaft conditions) by sensing the motor's back EMF to determine speed. The difference between the speed and a setpoint is used to close a sampled loop around the motor. A1 generates a pulse train. When the A1 output is high, Q1 is biased, Q3 turns off, and the motor back EMF appears after the inductive flyback stops, During this period, the S1 (a switch within the CD4016) input is turned on, and the 0.047-μF capacitor charges to the back EMF value. A2 compares this value with the setpoint, and the amplifier difference changes the A1 duty cycle, thus controlling motor speed. The setpoint is controlled by a -3-V signal (Ein) at the A2 noninverting input.   (View)

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Push-pull converter circuit diagram composed of TDA4718

Published:2011/8/1 2:48:00 Author:Ecco | Keyword: Push-pull converter

The push-pull converter circuit composed of TDA4718 is shown as the chart. It uses two switching elements to do on / off work and to prevent the transformer magnetic saturation, then it can increase conversion efficiency. Transformer windings N1, N2 and N3, N4 are not symmetrical around system, and the bias point of the hysteresis loop will move, that is magnetic bias, then the output voltage increase will result in saturation. Because the transformer windings will produce stray capacitance, therefore, the higher the frequency will result in more complex inductive coupling effect between wingings.   (View)

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ADJUSTABLE_SENSITIVITY_FIELD_STRENGTH_INDICATOR

Published:2009/6/29 2:24:00 Author:May

Circuit Notes The LED lights if the rf field is higher than the pre-set field strength level. Diodes should be germanium. Transistors (NPN) = 2N2222, 2N3393, 2N3904 or equivalent.   (View)

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Power_op_amp_bridge_amplifier_with_differential_output

Published:2009/7/24 23:27:00 Author:Jessie

The differential output of the LM12 (Fig. 10-46) amplifier almost doubles the voltage swing delivered to the load. The diodes clamp the outputs to the supplies.   (View)

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MEASURING_THRESHOLDS

Published:2009/6/29 2:23:00 Author:May

Upper and lower thresholds of noninverting comparator under test (A1) are read on DVM at end of capacitor charge and discharge cycles initiated by S1 and S2. With C1 discharged, relay L1 is energized. Closing S1 allows C1 to charge toward VCC. When upper threshold is reached, relay drops out and meter is read. Closing S2 starts discharge cycle which stops at lower threshold. Reverse relay connections when testing inverting comparator.—E. S. Papanicolaou, Comparator is Part of its Own Measuring System, EON Magazine, Aug. 5, 1974, p 76.   (View)

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Ultra_precision_instrumentation_amplifier

Published:2009/7/24 23:26:00 Author:Jessie

This circuit provides greater precision than that of the circuit in Fig. 3-4, but at the expense of bandwidth, as shown by the corresponding table.   (View)

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SEQUENTIAL_UJT_TIMER

Published:2009/6/29 2:22:00 Author:May

  (View)

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Power_op_amp_with_single_supply_operation

Published:2009/7/24 23:26:00 Author:Jessie

The output current of the LM12 (Fig. 10-46) bridged amplifier is proportional to differential-input voltage, thus eliminating the need for two supplies. If the output is a motor load (as shown), use output clamp diodes.   (View)

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SEQUENTIAL_TIMER_1

Published:2009/6/29 2:21:00 Author:May

By utilizing both halves of a dual timer it is possible to obtain sequential timing. By connecting the output of the first half to the input of the second half via a.001μF coupling capacitor sequential timing may be obtained. Delay t1 is determined by the first half and t2 by the second half delay. The first halfof the timer is started by momentarily connecting pin 6 to ground. When it is turned out (determined by 1.1R1C1), the second half begins. Its duration is determined by 1.1R2C2.   (View)

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SENSITIVE_FIELD_STRENGTH_METER

Published:2009/6/29 2:18:00 Author:May

Circuit Notes Increased sensitivity gives field strength reading from low power transmitters. Operat-ing range 3-30 MHz. To operate, adjust R for 1/3 to 1/2 scale reading. RFC = 2.5 mH choke, C =1.000 pF, R = 50 K pot, M = 0－1 mA, D = 1N34 or 1N60 (Germanium), Q = NPN (RCASK3020, 2N3904 or equivalent).   (View)

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10_W_CLASS_A

Published:2009/6/29 2:17:00 Author:May

Highly stable circuit uses easily obtainable components. Transistor types are not critical. Shortdrcuit protection is provided by constantcurrent source D1-Tr2-Tr5-Tr4. Output transistors Tr5 and Tr6 requirb heatsinks ca pable of dissipating at least four times rated output power. D1 and Tr2 should be in thermal contact.-A. H. Calvert, Class A Power Ampli-fier, Wireless World, June 1976, p 71.   (View)

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CURRENT_CONTROL_FOR_POWER_SWlTCH

Published:2009/6/29 2:15:00 Author:May

Circuit makes power supply current increase gradually from zero when supply is tumed on, to eliminate transients that sometimes cause alarming loudspeaker thumps in audio systems. Current through silicon power diode D1 is controlled by voltage on C1, which charges up after closing of switch with time constant C1R2R3/(R1 + R2). When switch is opened, rundown of supply curent is controlled by discharge of C1 through R2. Article also covers use of two current control circuits in tandem for handling higher Ioads.-P. J. Briody, Power Supply Delayed Switching, Wireless World, March 1975, p 139-141.   (View)

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3_W_DIFFERENTIAL

Published:2009/6/29 2:14:00 Author:May

Upper Motorola MC1554 power amplifier is connected in standard configuration for noninverting gain of 9, while lower IC has inverting gain of 9 to give effective overall voltage gain of 18. Input impedance of upper amplifier is 10K while that of lower amplifier is 1K, with unequal input coupling capacitors providing required match of frequency responses. Differential output connection allows output voltage swing to exceed powersupply voltage.- The MC1554 One-Watt Monolithic Integrated Circuit Power Amplifier, Motorola, Phoenix, AZ, 1972, AN-401 p 4   (View)

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LOW_COST_MICROWAVE_FIELD_STRENGTH_METER

Published:2009/6/29 2:13:00 Author:May

Circuit Notes When operating, a waveguide directs energy onto a crystal detector. The diode I shown is for X-band operation. The waveguide is a 1 1/2 inch piece of plastic tubing with the ends flared. The plastic is coated with an electroless copper solution to provide a conducting surface. The dimensions are not critical. For calibrated readings, the meter is placed in a known field or else compared to a calibrated meter. To operate the meter, point it away from the signal. Switch the meter to the de-sired range, and adjust the zero control for a 0 reading. Then point the waveguide at the sig-nal, and read field strength directly.   (View)

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Pozoer_op_amp_servo_amplifier_rate_generator

Published:2009/7/24 23:36:00 Author:Jessie

This servo provides an output speed that is proportional to the input voltage, but with a rate signal to compress the dynamic range. This is done electrically by differentiating the servo error signal (as shown in Fig. 10-57A). The LM12 (Fig. 10-46) provides current drive to the motor.   (View)

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FET_PREAMP_WITH_TONE_CONTROLS

Published:2009/6/29 2:13:00 Author:May

Developed for use with simple 2-W audio amplifier when testing very low-level output circuits and microphones. Will not load circuit to which input is connected. Optional bass/treble tone controls are included.-J. Schultz, An Audio Circuit Breadboarder's Delight, CQ Jan. 1978, p 42 and 75.   (View)

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5_V_from_four_cells_linear_regulation

Published:2009/7/24 23:35:00 Author:Jessie

Figure 8-98 shows a MAX667 linear regulator connected to provide a 5-V output from four cells. The input voltage range is 4 V to 16.5 V. The quiescent current (VIN = 6 V) is 10 μA, and the maximum load current (VIN = 6 V) is 250 mA. The dropout voltage is 100 mV with a 100-mA load. Figure 8-99 shows the efficiency curves. MAXIM BATTERY MANAGEMENT CIRCUIT COLLECTION, 1994, P. 21.   (View)

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THREE_LEVEL_COMPARATOR

Published:2009/6/29 2:12:00 Author:May

All three sections of CA3060 three-opamp array are used with CA3086 transistor arrays to provide three adjustable limits for comparator. If upprr orlower limit is exceeded, appropriate output is types of industrial control pplications.— Ciractivated until input signal retums to presecuit ideas for RCA Linear ICs, RCA Solid State lected intermediate limit. Suitable for many Division, Somerville, NJ, 1977, p 17.   (View)

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FSK_decoding_with_carrier_detect

Published:2009/7/24 23:35:00 Author:Jessie

This circuit is similar to that of Fig. 3-9, but it also uses the lock-detect section of the XR-2211 (Fig. 3-9C) as a carrier-detect option for FSK decoding. The lock-detect output at pin 6 is shorted to the data output at pin 7. The data output is disabled in the low state until there is a carrier within the detection band of the PLL, and pin 6 goes high to enable the data output. The minimum value of lock-detect filter capacitance CD (pins 3 and 4) can be calculated using: CD (inμF)=16/capture range in Hz. Large values of CD slow response time of the lock-detect output, and small CD values can result in chatter on the lock-detect output as an incoming signal approaches the capture-bandwidth frequency.   (View)

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STROBED_MICROPOWER

Published:2009/6/29 2:12:00 Author:May

Uses CA3080A var-iable opamp and CA3600E CMOS transistor array. Quiescent power drain from ±12V supply is only 10 μW, increasing to 420 μW when comparator is strobed on to make CA3080A active.— Circuit ideas for RCA Linear ICs, RCA Solid State Division, Somerville, NJ, 1977, p 16.   (View)

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