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Discriminator Circuits
Discriminators:  #-B     C-H     I-Q     R-Z

Last Updated on:
Monday, July 11, 2016 02:00 PM


Circuits Designed by Dave Johnson, P.E. :

 

12v Cooling Fan Thermostat -  This circuit will turn on a 12v DC powered cooling fan when the air temperature reaches a certain high temperature and will keep the fan turned on until the temperature drops below a second lower level. Both the high and low temperatures are both adjustable . . . [Circuit by David Johnson P.E.,  02/06/11]

 

1us Light Pulse Discriminator -  This circuit is designed to detect the narrow 1uS pulses produced by the above amplifier circuit. The clean logic type pulses produced by the discriminator are then sent to a frequency to voltage converter. The circuit is designed to process a pulse frequency . . . [Hobby Circuit designed by David A. Johnson P.E.,  03/11/99]

 

40Khz Ultrasound Receiver -  A X100 transistor amplifier is followed by a zero cross detector circuit, using a voltage comparator. The output is a TTL logic signal, corresponding to the received 40KHz signal . . . [Circuit by David Johnson P.E.,  01/29/06]

AC Peak Detector that is Precise -  This unique circuit uses a very inexpensive voltage comparator to form a peak detector. The DC voltage produced tracks the positive peak of the input signal. It works from about ten millivolts to about 10 volts peak to peak. The maximum frequency is about . . . [Hobby Circuit designed by David Johnson P.E.,  02/11/02]

 

Acceptable Voltage Indictor -  I have used this circuit many times in custom test fixtures where a simple go-no go indication was needed. The circuit can also be used to adjust a particular voltage be within specific high or low limits. The three LEDs will indicate if the voltage is . . . [Circuit by David Johnson P.E.,  02/09/02]

 

Amplifier for a Xenon Lamp Flash Detector  -  This circuit uses a small 2. 5mm square photo diode in conjunction with a 100mH coil to detect the short light flashes from a xenon lamp. The coil makes the circuit immune to normal room lights. Its 10mv sensitivity can detect light flashes from a range . . . [Circuit by David Johnson P.E.,  02/15/02]

 

Battery Charge Current Indicator -  This circuit turns on a LED whenever it detects at least 25ma of battery charge current . . . [Circuit by David Johnson P.E.,  07/23/06]

Links to electronic circuits, electronic schematics, designs for engineers, hobbyists, students & inventors:

12v Cooling Fan Thermostat -  This circuit will turn on a 12v DC powered cooling fan when the air temperature reaches a certain high temperature and will keep the fan turned on until the temperature drops below a second lower level. Both the high and low temperatures are both adjustable . . . [Circuit by David Johnson P.E.,  02/06/11]

 

1-Shot Provides Frequency Discrimination -  05/01/03  EDN Design Idea   You use a frequency discriminator to compare one signal frequency with another one. A functional feature, retriggering, of a monostable, one-shot 74xx123 multivibrator can yield frequency discrimination. Figure 1 shows a frequency discriminator that determines the relation of input-pulse frequency to a reference frequency. . .  [by Victor Aksenenka, CSRI Elektropribor, St Petersburg, Russia]

 

1us Light Pulse Discriminator -  This circuit is designed to detect the narrow 1uS pulses produced by the above amplifier circuit. The clean logic type pulses produced by the discriminator are then sent to a frequency to voltage converter. The circuit is designed to process a pulse frequency . . . [Hobby Circuit designed by David A. Johnson P.E.,  03/11/99]

2 buttons provide safe start -  07/06/00 EDN Design Idea   The circuit in Figure 1 provides a safety interlock that checks the actuation of two pushbuttons before enabling a relay. When you push both buttons, the circuit actuates the relay. At that point, you can release one of the switch. . .  [by Vincent Himpe, Alcatel Microelectronics, Desselgem, BelgiumVincent Himpe, Alcatel Microelectronics, Desselgem, Belgium]

2-Wire Thermistor 0°C to 100°C Temperature Transducer with 4mA to 20mA Output -  The LTC1040 is a monolithic CMOS dual comparator manufactured using Linear Technology’s enhanced LTCMOSTM silicon gate process. Extremely low operating power levels are achieved by internally switching the comparator ON for short periods of time. The CMOS output logic holds the output information continuously while not consuming . . .  [Linear Technology App Note, Mar 30th 2010]

 

40Khz Ultrasound Receiver -  A X100 transistor amplifier is followed by a zero cross detector circuit, using a voltage comparator. The output is a TTL logic signal, corresponding to the received 40KHz signal . . . [Circuit by David Johnson P.E.,  01/29/06]

 

5V Powered Thermistor Heating/Cooling Automatic Thermostat -  The LTC1040 is a monolithic CMOS dual comparator manufactured using Linear Technology’s enhanced LTCMOSTM silicon gate process. Extremely low operating power levels are achieved by internally switching the comparator ON for short periods of time. The CMOS output logic holds the output information continuously while not consuming . . .  [Linear Technology App Note, Mar 30th 2010]

 

A Seven Nanosecond Comparator for Single Supply Operation -  AN72 AN72 is an extensive discussion ofcauses and cures of problems in very high speed comparator circuits. A separate applications section uses7ns LT1394 in V-to-F converters, crystal oscillators, clock skew generators, triggers, sampling configurations and a nanosecond pulse stretcher. Appendices cover related topics. . . .  [Linear Technology]

 

Absolute Value Circuit (Full-Wave Rectifier) -  For negative inputs, the first section operates as a closed-loop inverter (A=-1) and the second stage is simply a buffer for the positive output. When the input signal is positive, the first opamp output remains saturated near ground and the diode becomes high-impedance, allowing the signal to pass directly to the buffer stage non inverted. The composite effect is a full-wave rectified waveform at the output of the buffer. . . .  [Linear Technology App Note, Jun 21, 2011]

 

Absolute-Value Circuit Delivers High Bandwidth -  05/15/03  EDN Design Idea   Most absolute-value circuits have limited bandwidth and high component count, and they require several matched resistors. The circuit in Figure 1 uses three fewer components than most absolute-value circuits require, and only two o. . .  [by Ron Mancini, Texas Instruments, Bushnell, FL]

 

Absolute-value comparator touts accuracy, size -  03/07/02  EDN Design Idea   A typical window comparator uses two comparators and a single op amp to determine whether a voltage is inside or outside a boundary region. Figure 1 shows a typical implementation. IC1 is an inverting op amp with a gain of –1. VREF and –VREF create the. . .  [by Teno Cipri, Engineering Expressions Consulting, Sunnyvale, CA]

 

AC Peak Detector that is Precise -  This unique circuit uses a very inexpensive voltage comparator to form a peak detector. The DC voltage produced tracks the positive peak of the input signal. It works from about ten millivolts to about 10 volts peak to peak. The maximum frequency is about . . . [Hobby Circuit designed by David Johnson P.E.,  02/11/02]

 

Acceptable Voltage Indictor -  I have used this circuit many times in custom test fixtures where a simple go-no go indication was needed. The circuit can also be used to adjust a particular voltage be within specific high or low limits. The three LEDs will indicate if the voltage is . . . [Circuit by David Johnson P.E.,  02/09/02]

 

Add Hysteresis to A Voltage Comparator -  03/04/10  EDN Design Idea   Positive feedback is a typical technique for distributing hysteresis around a comparator, provided that you have a resistive path between the comparator's output and the noninverting input. Positive feedback forms two threshold volt. . .  [by Luca Bruno, ITIS Hensemberger Monza, Lissone, Italy]

 

Amplifier for a Xenon Lamp Flash Detector  -  This circuit uses a small 2. 5mm square photo diode in conjunction with a 100mH coil to detect the short light flashes from a xenon lamp. The coil makes the circuit immune to normal room lights. Its 10mv sensitivity can detect light flashes from a range . . . [Circuit by David Johnson P.E.,  02/15/02]

 

An IC Voltage Comparator for High Impedance Circuitry -  Application Note. . .  [National Semiconductor]

 

AN-41: Precision IC Comparator Runs from +5V Logic Supply -  Application Note. . .  [National Semiconductor]

 

AN-87: Comparing the High Speed Comparators -  Application Note. . .  [National Semiconductor]

 

Applications of the LM392 Comparator Opamp Ic -  Application Note 04-Nov-1995. . .  [National Semiconductor]

 

Battery Charge Current Indicator -  This circuit turns on a LED whenever it detects at least 25ma of battery charge current . . . [Circuit by David Johnson P.E.,  07/23/06]


Discriminators:  #-B     C-H     I-Q     R-Z


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