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128 Threads found on edaboard.com: High Voltage Divider
Hi, everyone! I need to make a circuit that can sense if the mains voltage is 240 or 380 volts. In case it detects about 380 volts, a relay should turn on. I guess I need a way to measure the mains voltage. It doesn´t have to be precise. Can I rectify and filter the mains, and use a voltage divider to scale down the (...)
a low frequency solution, like the X10 scope probe, will not work well with a microwave or even high frequency RF signal. I would NOT count on it being a 1/10th voltage divider either, since the spectrum an alyzer is a 50 ohm system, and a scope is typically a 1 Mohm system. I would put a 20 dB 50 ohm attenuator at the spectrum analyzer (...)
I am working on 3 phaseAC machine inverter. For measuring the motor phase voltages I use the following circuit 135315 In my project the op-amps supply voltage is +/-5VDC; the inverter module supply voltage is +15VDC. These power supplies are deried from an isolated +5VDC supply. So the op-amps and the inverter module (w
My mistake, only one voltage divider is needed to make the half-supply bias voltage. The filter capacitor for it must have a high enough value for it to be almost a short circuit at your lowest frequency. Your biasing for the lowpass filter is correct.
If you want it done with 0.00% loss, that's easy. Quit now. Resistive dividers have not only the inherent loss, but a dismal consistency of output relative to loading. Only a high-Z load would make any sense for using that. Depending on how many different voltages and how many at once, a multi-tapped xfmr with switches could be viable. (...)
A transformer provides isolation so that you do not electrocute yourself. The drill requires a high current. A voltage divider supplies a low current. Why don't you replace the battery?
Hi All, I am planning to measure the AC RMS using microcontroller. Because of size constrain I don't want to use step down transformer. By using bridge rectifier the input AC voltage is converted into DC, then using voltage divider network the rectifier volt is reduced and out put of the voltage divider (...)
It probably has more to do with the writer not being fluent in English. Basically unless the know resistor is a high precision resistor (e.g. 0.1%) then your accuracy will vary according to that known precision. If you use a 10% resistor you won't get better than 10% accuracy in the unknown resistor value and if that unknown resistor is off by 10
Assuming you are using 5V VDD and 5V as the ADC reference: 1. Use a 10:1 potential divider. If the current into the divider has to be very low (=high value resistors) follow it with a buffer amplifier. 2. Depends on the response time you need but simplest method is to convert the AC to DC and use a potential divider for the (...)
Won't consider AD817 as general purpose OP. Like other high bandwidth OPs, it has larger output current. But the OP would get quite hot. Still think that a passive resistor circuit is preferable.
If the sensor has an internal pull-up to 12V, try to adjust the high level voltage with a pull-down to ground, e.g. 2k.
You surely need a voltage divider for the high voltage. How much load current can you accept? Should we assume common ground of both voltage sources or do you need isolation?
An electrolytic capacitor is inaccurate because it has a wide range of tolerance. So if it is rated at 100uF then it could be anywhere from 50uF to 200uF. A polarized capacitor should never have reversed polarity. You got no sound because the low input resistance of what the high resistance filter is driving created a voltage divider. The RC (...)
Hello, I have 500V to 1000V DC output from comibination of solar Panels. Is it possible to design a circuit which will represent 500Volts to 1000Volts DC range in 0V to 10Volts DC so that I can control my output device as per the voltage. Similar to solar dusk to dawn street light, but high voltage. eg: 500V will be represented as 0V (...)
yep, AVRs common ADC has a recommended input impedance of no more than 10Kohm... that voltage divider seems a little to high...
I believe you know that +/- 35V is no voltage range for a standard OP. So you have essentially these options: - use an expensive high voltage OP - design a discrete buffer amplifier - use a passive voltage divider, similar to an oscilloscope input
If you section the design into 3 stages; 1st stage is a differential input current amplifier with Vgain controlled by R2/R1 ratio =1 and serves to raise input impedance and control loop V gain from R3, R1 divider ratio. 2nd stage is a single input differential output voltage amp. with high V gain controlled by CC
You won't use "very high" resistor values. Microcontroller ADC inputs work best with moderate source impedance, e.g. 1 - 5 kohms.
A differential amplifier with symmetrical voltage divider would be also my standard solution. It should be mentioned that it involves a leakage current according to the common voltage between high voltage and measurement circuit. The circuit must be designed to tolerate the leakage current, e.g. with (...)
I am trying to find a way to safely sample a high voltage output which will travel from about 1kV to 20kV (ramp). I think using a resistor divider should do the job. I have been successful at 1 kV - 2 kV range. I am just wondering if just by using a high impedance resistor will do the trick. Any advise?
A x10 'scope probe has a trimmer capacitor parallel with the input resistor to make a high frequency voltage divider so that the high frequencies are not attenuated too much by the input capacitance of the 'scope (the opamp and its input wiring) in your circuit).
Dear Sandip, Even if you use Optocoupler, you must choose a one which is socket compatible, otherwise if the optocoupler burns, it will render the PCB vague (unless you can manually replace the optocoupler, or willing to send the board for RMA and a session of high-temperature exposure). I would suggest a Capacitor voltage divider (since (...)
You over complicate it! The output voltage of that circuit can never go negative because there is no negative voltage supplied to it, however, by biasing the + (non-inverting) input at half supply voltage, you have offset the output by 2.5V even when there is no input voltage. I think you are mistaking (...)
For worst case low output you must use R1 at its high extreme (1010), and R2 at its low extreme (990). Similarly, for the worst case high output, you would use R1 at its low extreme (990), and R1 at its high extreme (1010).
Signal transformer rated for high voltage transient insulation (>10kV) may be simplest solution. Also a remote differential Amp could be used powered by the DMM. Consider 100:1 gain reduction with low current. and calibrate it. DC to sensor and AC couple to meter. Make sure the divider can handle worst case line impulse (...)
Consider how a scope probe acts as 10:1 divider with R1C1:R2C to get flat response and do the same for 1000:1 divider with equal RC, except C is leakage capacitance of PU conformal coating across R string for moisture protection. Then for small shunt R2, add equivalent C2, which prevents transient feedthru by flat response. Consider ESL in RC
The most elegant solution is the resistive potential divider, costs are in pence. Remember to limit the high voltage to Vcc. If you are after high speed you could compensate it. Frank
divider impedance too high?
what is the voltage of the solar panel ? if your resistor is only for sensing, you don't need a high power LEDs, you only need to have high resistance to avoid that you voltage divider will dssipate too much current,
Tektronix sells several high voltage probes, all the way to 20 kV:
The LM741 opamp has a very old design and has horrible high frequency response and slew rate. The extremely low value for some of the output and feedback resistors (R4 and R2) overloads the opamps. The value of R5 is so low that opamp U1 is not an integrator.
i have made a DC DC converter using pic microcontroller , input is 12vdc and output is 311vdc . For feedback , i have used voltage divider network ,so my question is " should i use a unity gain buffer after voltage divider to protect the microcontroller ADC pin from high voltage .?
Since you want to measure it using an ADC which will most likely be connected to something else, you need to electrically isolate the high voltage from the low voltage. You can do this using high voltage capacitors in a similar voltage divider network to a resistor (...)
There are some very critical values to resonate exactly at 750kHz and 1500 kHz. The cap divider ratio is not critical as your middle cap C3 = 70pF dwarfs the 4.7pF. Note I increased the value to tune it. If YOU MUST verify the cap ratio, DO it with standard 50 Ohm generator and 2 caps only, otherwise just use predicted ratio. Then tune the oth
A high voltage difference amplifier such as the 1N146 should do what you want.
If both devices works at same voltage level no need to worry you can connect directly. If one is at 3.3v and another is at 5v and if it is UART interfacing (RX, TX) you can use simple resistor divider to connect the Tx of 5v chip to Rx of 3.3v chip. Connect directly the 3.3v Tx to Rx of 5v chip. (For CMOS high is >= 2/3Vdd to Vdd which (...)
Yeah that's way too high, try decreasing them by a couple orders of magnitude at least. Buffering the voltage with an op amp would help too.
Hi, I have an H bridge IGBT circuit. I want to probe VCE of the two high side IGBTs. Obviously , the signals to be measured are differential. I have an oscilloscope which can measure differential signals. The issue is that it can measure a maximum of 25 V and I am applying 48V dc as the H bridge power. I have got an x10 single ended probe.Can I
how can I get 12V (30 ma) dc from 400V dc
- Connect a voltage divider (R3/R4) from supply to the inverting OP input to provide an adjustable reference voltage - Derive expressions for low and high threshold voltages - Calculate R1/R2 and R3/R4 ratio to meet your specifications Rather visually, R1/R2 ratio sets the hysteresis (difference (...)
Hello, Assuming a high voltage capacitor charged (10-15KV). How can I convert this to say 12v or so for charging a lower voltage capacitor?
Hi use a comparator with a Opamp and a 3.1V zener..... choose the high resistance for voltage divider and zener series resistor values so that It wont drain much power. Many lousy old 741 opamps DO NOT WORK with a supply voltage as low as 5V and their supply current is fairly high. The LM10 (...)
This is a terrible idea(sorry). This will only work if your load is very high impedance, otherwise, any current draw will cause a voltage drop across the pot.
If ground to neutral isolation is required and a measurement transformer isn't an option, symmetrical voltage dividers and differential amplifiers are probably the next best variant, as used in oscilloscope high voltage differential probes.
hi are you talking about the resistor||capacitor in series with 220VAC and battery (before rectifier) ? if yes, this is used to step down the high AC voltage. Google "Transformer less power supply"
It should be obvious. You want a high input impedance to minimize the voltage error due to the source impedance. You want a low output impedance to minimize the voltage error due to the load impedance. In both case the two impedances are in series and thus will give a voltage drop due to the voltage (...)
4V7 zener diode would need an additional voltage divider, 4V3 gives still to high output voltage (about 3.6 V), how about using a 3V9 Z-diode? You can tune the output voltage with a small resistor in series with the diode (10 ohms range)
why worry about high current or over-voltage? is your power supply that bad? I think you worry too much, but if it keeps you from sleeping, then put in a proper power supply
Use high Value resistor make divider & Apply divider output to Opto input. Before this add half or full wave rectifier with capacitor for smoothing DC level. at output we get isolated output 20k to 200k for the i/p resistor and capacitor range 470uf/63v,diode of 1W these range enough for that circuit guys..
U1 EN Enable / Under voltage Lock-Out / Shutdown input An external voltage divider can be used to set the line undervoltage lockout threshold. If the EN pin is left unconnected, a 6 ?A pull-up current source pulls the EN pin high to enable the regulator.