Pulse detector

I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

 

[Pimpom]

On 4/23/2020 10:42 PM, edward.ming.lee@gmail.com wrote:

I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Not a typo. Those are PNP transistors and they need negative
collector supplies.

 

[Phil Hobbs]

On 2020-04-23 13:25, Pimpom wrote:

On 4/23/2020 10:42 PM, edward.ming.lee@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange.  Could it be a typo?


Not a typo. Those are PNP transistors and they need negative collector
supplies.

It is a bit confusing--nowadays one generally tries to draw schematics
with current flowing generally downward and signals generally to the right.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Fred McKenzie]

In article <dcdb37e9-6bb6-4df5-8f54-9bf5f3f5d095@googlegroups.com>,
edward.ming.lee@gmail.com wrote:

I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

Edward-

The minus voltage appears to be correct for PNP transistors.

Minus 12 Volts might work for a lower amplitude pulse.

Fred

 

On Thursday, April 23, 2020 at 10:25:52 AM UTC-7, Pimpom wrote:

On 4/23/2020 10:42 PM, edward.ming.lee@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?


Not a typo. Those are PNP transistors and they need negative
collector supplies.

OK, i am used to drawing positive on top.

What if i replace them with NPN, fliping the diodes, lower the two 18K to 1K and tie to ground?

I think the first two Qs are just flip flop and the third integrator. I just need the single rail positive version.

 

[whit3rd]

On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:

I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

 

On Thursday, April 23, 2020 at 11:40:39 AM UTC-7, Tauno Voipio wrote:

On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:
On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.


How fast?

1Khz

> Is it repetitive?

Yes.

 

[John Larkin]

On Thu, 23 Apr 2020 10:12:54 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

How about diode+capacitor+discharge pushbutton?

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:

On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

 

[Tauno Voipio]

On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:

On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.

How fast?

Is it repetitive?


The 'simple circuit diagram' smells very old.

--

-TV

 

On Thursday, April 23, 2020 at 12:01:32 PM UTC-7, Ricky C wrote:

On Thursday, April 23, 2020 at 2:44:35 PM UTC-4, edward...@gmail.com wrote:
On Thursday, April 23, 2020 at 11:40:39 AM UTC-7, Tauno Voipio wrote:
On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:
On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.


How fast?

1Khz

Is it repetitive?

Yes.

At one kHz definitely use an op amp.

You could Google "op amp peak detector circuit" or here are a couple of examples.

https://www.circuitlab.com/circuit/y453h7/precision-active-peak-detector/

OK, that might work.

 

On Thursday, April 23, 2020 at 11:55:12 AM UTC-7, Ricky C wrote:

On Thursday, April 23, 2020 at 1:40:17 PM UTC-4, edward...@gmail.com wrote:
On Thursday, April 23, 2020 at 10:25:52 AM UTC-7, Pimpom wrote:
On 4/23/2020 10:42 PM, edward.ming.lee@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?


Not a typo. Those are PNP transistors and they need negative
collector supplies.

OK, i am used to drawing positive on top.

What if i replace them with NPN, fliping the diodes, lower the two 18K to 1K and tie to ground?

I think the first two Qs are just flip flop and the third integrator. I just need the single rail positive version.

Enter it into LTspice and try it. First I'd enter the circuit as is to make sure it works as expected. Then modify it as you are looking to do with the positive supply and eliminating the other supply.

The original circuit (flip it horizontally makes more sense) might be good for negative signal. I am measuring positive signal; so, i want to change to NPN.

> What speed do you need from this? How high, often and wide are your pulses?

10% duty cycle of 1Khz. Accuracy might not be too critical.

 

[Ricky C]

On Thursday, April 23, 2020 at 2:44:35 PM UTC-4, edward...@gmail.com wrote:

On Thursday, April 23, 2020 at 11:40:39 AM UTC-7, Tauno Voipio wrote:
On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:
On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.


How fast?

1Khz

Is it repetitive?

Yes.

At one kHz definitely use an op amp.

You could Google "op amp peak detector circuit" or here are a couple of examples.

https://www.circuitlab.com/circuit/y453h7/precision-active-peak-detector/

https://www.brainkart.com/article/Peak-Detector-using-Operational-Amplifier_36013/

or here's a 35 minute educational video by our favorite public speaker.

https://www.youtube.com/watch?v=jllsqRWhjGM

--

Rick C.

+ Get 1,000 miles of free Supercharging
+ Tesla referral code - https://ts.la/richard11209

 

[Ricky C]

On Thursday, April 23, 2020 at 1:40:17 PM UTC-4, edward...@gmail.com wrote:

On Thursday, April 23, 2020 at 10:25:52 AM UTC-7, Pimpom wrote:
On 4/23/2020 10:42 PM, edward.ming.lee@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?


Not a typo. Those are PNP transistors and they need negative
collector supplies.

OK, i am used to drawing positive on top.

What if i replace them with NPN, fliping the diodes, lower the two 18K to 1K and tie to ground?

I think the first two Qs are just flip flop and the third integrator. I just need the single rail positive version.

Enter it into LTspice and try it. First I'd enter the circuit as is to make sure it works as expected. Then modify it as you are looking to do with the positive supply and eliminating the other supply.

What speed do you need from this? How high, often and wide are your pulses? This is the sort of thing I would likely use an op amp for. You don't have to worry about biasing and other messy details. An op amp, a diode and a few gain setting resistors do the job.

--

Rick C.

- Get 1,000 miles of free Supercharging
- Tesla referral code - https://ts.la/richard11209

 

On Thursday, April 23, 2020 at 2:10:43 PM UTC-7, boB wrote:

On Thu, 23 Apr 2020 12:05:26 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 12:01:32 PM UTC-7, Ricky C wrote:
On Thursday, April 23, 2020 at 2:44:35 PM UTC-4, edward...@gmail.com wrote:
On Thursday, April 23, 2020 at 11:40:39 AM UTC-7, Tauno Voipio wrote:
On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:
On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.


How fast?

1Khz

Is it repetitive?

Yes.

At one kHz definitely use an op amp.

You could Google "op amp peak detector circuit" or here are a couple of examples.

https://www.circuitlab.com/circuit/y453h7/precision-active-peak-detector/

OK, that might work.


Yeah, that's a peak voltage detector.

Next for when to capture that voltage (DutyCycle = 10%), maybe an R-C
LPF and a window comparator circuit... Use two copmareators to
trigger the peak V capture (whatever you need to do with it) when the
duty cycle is 10% of the full range voltage ?

Yes, that's what i need. Should have search on "peak detector" instead of "pulse detector". It's just a simple sample and hold of the input, then using several comparators to trigger on the voltage level.

 

[Ricky C]

On Thursday, April 23, 2020 at 5:15:56 PM UTC-4, edward...@gmail.com wrote:

On Thursday, April 23, 2020 at 2:10:43 PM UTC-7, boB wrote:
On Thu, 23 Apr 2020 12:05:26 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 12:01:32 PM UTC-7, Ricky C wrote:
On Thursday, April 23, 2020 at 2:44:35 PM UTC-4, edward...@gmail.com wrote:
On Thursday, April 23, 2020 at 11:40:39 AM UTC-7, Tauno Voipio wrote:
On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:
On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.


How fast?

1Khz

Is it repetitive?

Yes.

At one kHz definitely use an op amp.

You could Google "op amp peak detector circuit" or here are a couple of examples.

https://www.circuitlab.com/circuit/y453h7/precision-active-peak-detector/

OK, that might work.


Yeah, that's a peak voltage detector.

Next for when to capture that voltage (DutyCycle = 10%), maybe an R-C
LPF and a window comparator circuit... Use two copmareators to
trigger the peak V capture (whatever you need to do with it) when the
duty cycle is 10% of the full range voltage ?

Yes, that's what i need. Should have search on "peak detector" instead of "pulse detector". It's just a simple sample and hold of the input, then using several comparators to trigger on the voltage level.

A 10% duty cycle, 1 kHz pulse can be measured quite well using a single chip, as small as 8 pins.

--

Rick C.

-- Get 1,000 miles of free Supercharging
-- Tesla referral code - https://ts.la/richard11209

 

[boB]

On Thu, 23 Apr 2020 12:05:26 -0700 (PDT), edward.ming.lee@gmail.com
wrote:

On Thursday, April 23, 2020 at 12:01:32 PM UTC-7, Ricky C wrote:
On Thursday, April 23, 2020 at 2:44:35 PM UTC-4, edward...@gmail.com wrote:
On Thursday, April 23, 2020 at 11:40:39 AM UTC-7, Tauno Voipio wrote:
On 23.4.20 20:48, edward.ming.lee@gmail.com wrote:
On Thursday, April 23, 2020 at 10:43:52 AM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:13:00 AM UTC-7, edward...@gmail.com wrote:
I am looking for a voltage detector of a 10% duty cycle waveform.

This is close to what i need, best if it works with 12V:

https://www.simplecircuitdiagram.com/2150-peak-pulse-voltmeter/

The -20V at the top seems strange. Could it be a typo?

Wondering if i can scale it down to 12V.

Any other IC or circuit to do this?

What, exactly, is "this"? Do you really want to hold the peak DC voltage of an
incoming signal for a few milliseconds, or until you reset, or do you want to
measure that peak height?

Waveforms don't have 'a' voltage, and 'detector' is not very descriptive.

I want to measure the peak DC voltage of a 10% duty cycle signal.


How fast?

1Khz

Is it repetitive?

Yes.

At one kHz definitely use an op amp.

You could Google "op amp peak detector circuit" or here are a couple of examples.

https://www.circuitlab.com/circuit/y453h7/precision-active-peak-detector/

OK, that might work.

Yeah, that's a peak voltage detector.

Next for when to capture that voltage (DutyCycle = 10%), maybe an R-C
LPF and a window comparator circuit... Use two copmareators to
trigger the peak V capture (whatever you need to do with it) when the
duty cycle is 10% of the full range voltage ?

 

[whit3rd]

On Thursday, April 23, 2020 at 10:48:11 AM UTC-7, edward...@gmail.com wrote:

> I want to measure the peak DC voltage of a 10% duty cycle signal.

The simplest approach for that (used with proportional counter pulses) is
a peak detect/hold/convert-to-time-delay-and-count circuit
called a Wilkinson A to D converter.

 

[whit3rd]

On Thursday, April 23, 2020 at 3:55:42 PM UTC-7, whit3rd wrote:

On Thursday, April 23, 2020 at 10:48:11 AM UTC-7, edward...@gmail.com wrote:

I want to measure the peak DC voltage of a 10% duty cycle signal.

The simplest approach for that (used with proportional counter pulses) is
a peak detect/hold/convert-to-time-delay-and-count circuit
called a Wilkinson A to D converter.

Basic circuit is an op amp follower on the input voltage, feeding a diode and capacitor
(output through diode to capacitor, feedback from the capacitor). When a peak
passes, the diode reverse-biases, and the op amp output goes to the negative rail.
Then you disconnect the op amp (it's done its job) and either directly
voltage-measure the capacitor, OR connect an accurate current-sink to
the capacitor and count clock pulses as it discharges to zero volts.

 

[Ricky C]

On Thursday, April 23, 2020 at 7:06:38 PM UTC-4, whit3rd wrote:

On Thursday, April 23, 2020 at 3:55:42 PM UTC-7, whit3rd wrote:
On Thursday, April 23, 2020 at 10:48:11 AM UTC-7, edward...@gmail.com wrote:

I want to measure the peak DC voltage of a 10% duty cycle signal.

The simplest approach for that (used with proportional counter pulses) is
a peak detect/hold/convert-to-time-delay-and-count circuit
called a Wilkinson A to D converter.

Basic circuit is an op amp follower on the input voltage, feeding a diode and capacitor
(output through diode to capacitor, feedback from the capacitor). When a peak
passes, the diode reverse-biases, and the op amp output goes to the negative rail.
Then you disconnect the op amp (it's done its job) and either directly
voltage-measure the capacitor, OR connect an accurate current-sink to
the capacitor and count clock pulses as it discharges to zero volts.

Or you use a $0.60 MCU to digitize the 100 uS wide pulses at 100 kSPS, let software find the valid pulse measurements and you are done.

Why is everyone making this so hard? He didn't initially say he was measuring the pulses, but still, not sure what that implies. Does he want data to be sent to another computer? Does this need to drive a display? Is he looking for real time updates of each pulse? An average of some sort? Is the pulse height varying? Sounds like he wants window comparisons to produce a decision of some sort? All of the above is very easy to do in the same $0.60 MCU that is taking the measurement. It can send an output via RS-232, TTL signals, RF pulses or an amplitude modulated audio tone. It can even provide the universally hated output, a blinking LED.

This is a classic case of, "No, tell me the problem you are really trying to solve".

--

Rick C.

-+ Get 1,000 miles of free Supercharging
-+ Tesla referral code - https://ts.la/richard11209