Mar 2, 2008 · I want to build what I am sure is a simple project. I want to build a circuit that will fit into a standard home single gang electrical box. The box will have installed a standard 20A 120V outlet. What I want is to energize only one outlet. The other outlet will be controlled by the...

Mar 6, 2016 · Figure 1. Simple diode-drop current sensor with opto-isolator. The diodes drop a maximum of about 2.1 to 3 volts depending on current. OPTO1 is a bi-directional LED opto-isolator. These have infra-red LEDs internally and so forward voltage drop is about 1.2 V. R1 will limit the current to 10 mA.

Feb 6, 2020 · I am having issues finding a Variable current sensor switch that will precisely sense within the AC current ranges of 0-1 Amps (Test Range 0.001-0.2 Amps). Once the range of (0.001-0.2A) is sensed, I would like to trigger an alarm. Any suggestions on what I could use to sense such low AC currents?

Mar 9, 2024 · I've got a problem with designing a circuit. I've made a box that uses a current sensor module to detect when 230 volt current is flowing through it. This is designed so when a power tool is started, it automatically starts a vacuum cleaner to suck up sawdust generated by the power tool.

Aug 30, 2016 · An useful background reference was Linear's Current Sense Circuit application note. Also, if someone does identify, or introduce, a hall effect isolated current sensor like Allegro's range, but for low currents, we would happily change over to it.

Nov 30, 2023 · If you looked at the schematic of the voltage sensing module would see a similar type of bias circuit as that formed by the three resistors with the current sensor. So, the three external resistors on the current sensor and, the internal bias circuits of the ZMPT101B module are both needed to produce a mid-range DC offset equivalent to 50% of ...

Jan 2, 2021 · The circuit Ron Simpson posted above is a good circuit for sensing AC current. R6 is a 33 Ohm burden resistor while R7 and R8 form a voltage divider to get the AC out at a level of 2.5 VDC. Common problem is most A/D converters will not accept a negative input (when the sine wave goes below zero) so we set the output on a 2.5 VDC offset.

Sep 18, 2013 · The RFID sensor is this unit which basically acts as a switch that closes the circuit when the RFID tag is read by the sensor. This unit will keep the current flowing as long as the tag is present. Based on the location of the sensor the tag may be present for long periods of time. I want to be sure that won't cause damage/overheating/etc.

Aug 9, 2022 · The top resistor sets the approximate current. Whatever that current is, the same current flows through both the measured and reference resistors. If the measured resistor changes, or even if V+ changes, so will the current, but the ADC's result will still be proportional to Measured/Reference. I've played with my cheap DVM - it works that way.

Nov 16, 2022 · If you want to read a bidirectional current with an ADC that is unipolar you'll need to assign some voltage in the middle (not necessarily the center) to zero current. Then the voltage can change higher or lower from there over some range without exceeding the power supply rails. This is explained in the datasheet 9.2.2.2. Since the REF input ...