power supply circuit

0_TO_±10_V_PROGRAMMABLE_PEAK_DETECTOR

Published:2009/7/14 21:55:00 Author:Jessie

Principal components are Precision Monolithics CMP-11CJ voltage comparator, SMP81FY sample-and-hold amplifier, SN74LS136N open-collector EXCLUSIVE-OR gate package, and DG201 quad analog switch DC accuracy is within 5 mV at zero scale and within 10 mV at full scale. Resistors and diodes provide input overvoltage protection for comparator. Comparator continuously examines difference between analog input voltage and voltage peak held by sample-and-hold amplifier, If input exceeds held value, new input is held.-D. Soderquist, Polarity Programmable Peak Detector, Precision Monolithics, Santa Clara, CA, 1978,AN-27.   (View)

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VOLTAGE_LEVEL_LATCH

Published:2009/7/14 22:09:00 Author:Jessie

Circuit uses comparator to latch after input reaches predetermined threshold level. Output of IC1 then goes high and enables input of strobe Q2 to prevent output from going low. High level on reset input will turn off Q1, removing supply voltage from open collector output of IC1 and removing latch condition Comparator will operate on supplies ranging from single 5-V level to dual ±15V. – M. W Bair, IC Comparator Doubles as a Latch, EDN Magazine，April 20，1975，p 72．   (View)

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DUAL_LIMIT_DETECTOR

Published:2009/7/14 22:07:00 Author:Jessie

Provides 12-V output when applied DC input signal exceeds reference high limit established by setting of R1 or falls below reference low limit established by setting of R2. When input drops below low limit, CA3080 changes CA3094 to high-output condition. Output is low in voltage window between limits (dead zone).-E. M. Noll, Linear IC Principles, Experiments, and Projects, Howard W. Sams, Indianapolis, IN, 1974, p 317-318.   (View)

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WINDOW_DETECTOR

Published:2009/7/14 22:05:00 Author:Jessie

Connections shown for 322 comparators give high output only when input voltage is between thresholds set by R2 and R3 (within voltage window). Output of circuit goes low whenever input is below threshold 1 or above threshold 2.-W. G. Jung, IC Timer Cookbook, Howard W. Sams, Indianapolis, IN, 1977, p 153.   (View)

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SOLID_STATE_DELAY_WITH_A_C_OUTPUT

Published:2009/7/14 22:19:00 Author:Jessie

Timing sequence is initiated by switch, which applies power to ujt circuit. When emitter voltage of vie reaches peak point, C1 remains charged and vie oscillates at high frequency. Resulting pulses turn on scr’s through pulse transformer, applying voltage to load.- Transistor Manual, Seventh Edition, General Electric Co.1964, p 322.   (View)

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LEVEL_INDICATOR

Published:2009/7/14 22:10:00 Author:Jessie

Visual indication of voltage level is achieved with two TIL203 LEDs, three resistors, and any opamp that can provide 15-mA output current. If input voltage momentarily or permanently exceeds most positive reference level, LED1 is switched on. If voltage falls below negative or least positive reference level, LED1 goes off and LED2 comes on. Article gives design equations for determining values of R1 and R2. For levels of +2 V to turn LED1 on and -1.2 V to turn LED2 on, both R1 and R2 are 10K.-E. J. Richter, Op Amp Makes Visual Level Indicator, EDN Magazine, May 5, 1974, p 73.   (View)

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LONG_DELAYS

Published:2009/7/14 22:31:00 Author:Jessie

Delays up to 2 hours are obtained, using unijunctiom transistor Q1 as trigger for scr and Q2 as free-running oscillator. Only 2 na through timing resistor R1 will provide triggering.-D. V. Jones, Quick-On-The-Trigger Design, Electronics, 38:12, p 105-110.   (View)

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5_V_PEAKS_UPTO_2_MHz

Published:2009/7/14 22:31:00 Author:Jessie

Peak-to-peak detector using Optical Electronics 9412 opamps gives DC output voltage equal to peak-to-peak amplitude of sine-wave input voltage Opamp charges memory capacitor Cm during negative half of input cycle and performs DC clamp(restoration) on positive half. Circuit has high input impedance With 0.1-μF memory capacitor, 10-V pulse is acquired in 10μS，For 5-V sine-wave input, maximum frequency is 0.8 MHz, but 0.01-μF memory capacitor boosts frequency capability to 2 MHz, - A Wideband Peak-to-Peak Detector, Optical Electronics, Tucson, AZ、Application Tip 10176.   (View)

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LED_INDICATES_SIGNAL_LEVEL

Published:2009/7/14 22:32:00 Author:Jessie

Circuit is adjusted so opamp turns on LED at desired signal level as set by R1 Opamp is operated without feedback resistor to have maximum gain, so small input signal produces very large output signal Values shown for R2 and R3 give turn-on voltage of 0.9 V for LED．-F. M. Mims, Integrated Circuit Projects, vol. 4, Radio Shack, Fort Worth, TX, 1977, 2nd Ed., p 70-75.   (View)

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MICROPOWER_VOLTAGE_TO_FREQUENCY_CONVERTER

Published:2009/7/14 22:43:00 Author:Jessie

This voltage-to-frequency converter takes full advantage of the LTC1441's low power consumption under dynamic conditions. A 0- to 5-V input produces a 0- to 10-kHz output with 0.02 percent linearity, 60 ppm/°C drift, and 40 ppm/V supply rejection. Maximum current consumption is only 26μA, 100 times lower than that of currently available circuits. C1 switches a charge pump, composed of Q5, Q6, and the 100-pF capacitor, to maintain its negative input at 0 V. The LT1004s and associated components form a temperature- compensated reference for the charge pump. The 100-pF capacitor charges to a fixed voltage; hence, the repetition rate is the circuit's only degree of freedom to maintain feedback. Comparator C1 pumps uniform packets of charge to its negative input at a repetition rate precisely proportional to the input voltage-derived current.This action ensures that circuit output frequency is strictly and solely determined by the input volt-age. Start-up or input overdrive can cause the circuit's ac-coupled feedback to latch. If this occurs, C1's output goes low; C2, detecting this via the 2.7-MΩ/0.1-μF lag, goes high. This lifts C1's positive input and grounds the negative input with Q7, initiating normal circuit action.   (View)

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LASER_MODULATION_WITH_CURRENT_SOURCE

Published:2009/7/14 11:56:00 Author:May

Because atmospheric turbulence can become bothersome, any low-frequency baseband intensity modulation will become corrupted over long distances. To overcome this limitation, the information must be frequency-modulated up to 200 kHz in this manner. To obtain a more desirable current modulator for subcarrier modulation, use a transistor as a variable-current source to vary the current through the laser. Here the quiescent operating current through the laser is set at 4.1 mA by a potentiometer in the base bias circuit. Assuming a 0.7-Vdc drop across the transistor base-emitter junction and a 1000-Ω resistor in the emitter lead, the quiescent bias voltage from base to ground is 4.8 Vdc. The input voltage must vary 1.4 V p-p to cause a ±0.7-mA current variation through the laser. To effect this, the modulation signal source must provide up to a 1.4-V p-p signal into the laser current modulator circuit.   (View)

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2_10V_P_P_TRUE_RMS_T0_600_kHz

Published:2009/7/15 2:38:00 Author:Jessie

Input waveform is squared by first Motorola MC1594 multiplier, and current output is converted to voltage by opamp for driving second multiplier which has capacitor in feedback path to perform averaging function. Second opamp is used with second multiplier as feedback element to produce square-root configuration required for giving true RMS value. Accuracy is within 1% over input voltage range.-K. Huehne and D. Aldridge, Multiplier/Op Amp Circuit Detects True RMS, Motorola, Phoenix, AZ, 1974, EB-20.   (View)

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IC_MILLIVOLTMETER

Published:2009/7/15 2:36:00 Author:Jessie

Provides switched ranges of 5 mV to 500 V. Use 2% resistors. Pushbutton connection to positive supply gives internal calibration check on 5-V and 50-V ranges. Adjust meter initially with Rm, to read 1.4 V on 5-V range. Back-to-back signal diodes provide overload protection. Power drain is so low that battery life is essentially shelf life.-D. A. Bundey, Where is Your Simplified, Sensitive, Milli-voltmeter?, 73Magazine, Sept. 1975, p 49-50.   (View)

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THREE_PHASE_REGULATOR

Published:2009/7/15 2:13:00 Author:Jessie

When used with three-phase static inverter employing scr's and magnetic amplifiers, provides 25.millisec recovery time when load is switched from 2.5 amp to 0. The three bridges use one zener diode in common as non-linear element. Silicon transistor amplifies unbalance in each bridge.-M. Lilienstein, Static Inverter Delivers Regulated 3-Phase Power, Electronics, 33:28, p 55-59.   (View)

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PRECISION_CONSIANT_CURRENT_SUPPLY

Published:2009/7/14 5:25:00 Author:May

Reference amplifier, consisting of integrated zener diode and npn transistor, acts with Q2 to maintain constant reference voltage across R4. Current through R4 equals load current except for relatively small base currents of Q2 and Q3. Current drift over l5 hours is less than 0.01%.- Trclnsislor Manual, Seventh Edition, General Electric Co.1964, p 233.   (View)

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EXPONENTIAL_FUNCTION_GENERATOR

Published:2009/7/15 3:14:00 Author:Jessie

Output is exponentially decoying curve in which exponent is determined by other components of system. Used in analog computer to integrate curve of dye concentration in blood stream to obtain now role.-R. L. Skinner and D. K. Gehmlich, Analog Computer Aids Heart Ailment Diagnosis, Electronics, 32:40, p 56-59.   (View)

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CONSTANT_CURRENT_SUPPLY

Published:2009/7/14 4:48:00 Author:May

Used to measure resistivity of semiconductors rapidly and accurately. Switch gives choice of 0.5, 5, and 50 ma. Values are read from dial settings rather than meters, to increase accuracy-P. J. Olshefski, Constant. Current Generator Measures Semiconductor Resistance, Electronics, 34:47, p63.   (View)

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TEMPERATURE_COMPENSATED_CURRENT_SOURCE

Published:2009/7/14 4:44:00 Author:May

Presents 1,000 meg of output impedance while supplying up to 200 no of temperature-compensated current. Germanium diodes serve as compensating network drawing 1.3 ma. Based on fact that matched transistor pairs have base-current temperature coefficients that are predictable as function of operating current-C. C. Hanson, Low. Drift Current Generator Compensates for Temperature, Electronics, 39:12, p 108-109.   (View)

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LASER_FLASH_TUBE_SUPPLY

Published:2009/7/14 4:38:00 Author:May

Variable pulse forming network sends rectangular pulses of current through lash tube when network is discharged by ignitron used as switch. Resulting pump action on ruby crystal then produces laser beam for optical ranging up to 3 miles.-M. L. Stitch, E. J. Woodbury and J. H. Morse, Optical Ranging System Uses Laser Transmitter, Electronics, 34:16, p 51-53.   (View)

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l_MA_CONSTANT_CURRENT_SCR_SOURCE

Published:2009/7/14 4:35:00 Author:May

Use of high-breakdown-voltage 2N1599 scr gives 0.25% regulation at 1 ma for input volt-ages of 10 to 400V. Output current can be adjusted up to 10%. Differential amplifier Q1-Q2 compares sampled output current with voltage across reference zener.-R. H. Crawford, 400-Volt SCR Constant-Current Source, EEE, 12:3, p74.   (View)

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