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Opto-Isolator Coupler Circuits, Page 2
Opto Isolators: #'s - N O - Z
Last Updated on:
Friday, July 18, 2008 11:33 AM
| Circuits Designed by Dave Johnson, P.E. : |
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TIME TO DUST INDICATOR
I thought about this circuit when I heard that a lot cleaning personal in hotels were either dusting rooms more often than necessary or not enough. I have not yet built and tested this circuit
completely but in concept it should work. The circuit draws very low current from a +3v battery and could be housed in a package similar to a small ashtray. The assembly might be placed in a
suitable out of the way area to collect dust. It would alert a maid when it was time to dust the room. The circuit detects dust with an infrared LED that is pulsed so its light shines onto a
smooth flat plate. Any dust settling onto the surface is detected by a phototransistor, mounted at a 90-degree angle from the LED. When the dust reaches a particular level, sufficient light is
reflected into the phototransistor to change the logic state of the circuit to an alarm condition. The alarm output could be connected to a beeper, a flashing LED or to one of the LED flashing
circuits in this hobby circuit section.
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Links to electronic circuits, schematics, or diagrams for engineers, hobbyists, students &
inventors: |
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OptoCoupled Gate Detects Motor Operation: 02/02/98 EDN-Design Ideas / (Electronic Circuit diagram added 03/03) |
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Optocoupler extends high side current sensor to 1 kV: 03/01/01 EDN-Design Ideas / (added 11/05) |
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Optocoupler isolates Shift Registers: 01/20/00 EDN-Design Ideas / (added 05/03) |
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Optocoupler simplifies Power line monitoring: 01/10/02 EDN Design Ideas / (added 1/05) The use of a
linear optocoupler and a capacitor-based power supply yields a simple, yet precise power-line-monitoring system. The circuit in Figure 1 converts the 110V-ac power-line voltage to an ac output
voltage centered at 2.5V, covering 0 to 5V. The circuit isolates the output signal from the power line. ... |
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Optocouplers are handy for motor Drive: 06/13/02 EDN Design Ideas / (added 1/05) Figure 1a shows a
latching circuit based on an optocoupler, IC1. If the off switch remains closed, pressing the on switch powers the LED in the optocoupler. Thus, the transistor in IC1 turns on. You can now
release the on switch, and the transistor remains on. You must adapt the current-limiting resistor, R, to the power-supply voltage and the optocoupler's characteristics.... |
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Optoisolator Block Occupancy Detector: (Electronic circuit added 7/03) |
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Phone Wire RJ 11 jacks and optocouplers Build a Bus: 12/24/04 EDN Design Ideas / (added 1/05) Although
cutting-edge technology reaps publicity, the real world often runs on modest hardware that's just "good enough" for home automation, alarm systems, and equipment-monitoring application |
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RS232 to RS232 Port Powered Optical Isolator: Brochure with schematic in PDF format / (circuit added 7/02) |
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RS232C Circuit has Galvanic Isolation: 02/04/99 EDN-Design Ideas / (added 5/03) You can obtain longer transmission
distances with the RS-232C interface if you use galvanic isolation between the two linked terminals. Galvanic isolation also eliminates problems arising from disparate potentials between
terminals. Using two MAX860/861 ICs and two TPL2200 optoisolators, you can obtain galvanic isolation for three-wire transmission without external supplies (Figure 1). The MAX860/861 circuits,
which generate two voltages of different polarity, regardless of the polarity of TxD, which provides the supply voltage, are the basis of the design.... |
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Temperature Sensor uses I2C isolator: 06/06/96 EDN Design Ideas / (added 6/03) You can couple an LM75 digital
output-temperature sensor through an isolated I2C (interintegrated circuit) interface (see Reference) as shown in Figure 1. Electrically isolating the sensor allows operation in situations
prone to high common-mode voltages; it's also useful in breaking ground loops. IC1 and IC2 comprise a bidirectional isolator. |
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TV / Radio Antenna Cable Galvanic Isolator: (added 8/02) |
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Opto Isolators: #'s - N O - Z |
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