Positive Feedback: Howard Armstrong 1st Great Invention!
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Date: 2022-12-27
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Comments and reviews: 20
Jim
I remember as an elementary school student assembling a Heathkit going through labs of various stages of radio.
The Heathkit was a vacuum tube receiver. I remember one stage was just a diode (tube or crystal, I don't remember) and hearing 30 hz
hum and then regenerative feedback through a triode tube and a complete superhetrodyne receiver. With boyish enthusiasm,
I thought the name superhetrodyne sounded really cool. This was with a hot soldering iron on a metal chasis.
The difficulty of the point to point wiring gave me a great appreication of printed circuts. I was barely able to follow the labs
and never did anything original. But, my dad who was an electrical engineer and worked for a decades later version
of the company David Sarnoff founded, RCA was proud of me.
reply
I remember as an elementary school student assembling a Heathkit going through labs of various stages of radio.
The Heathkit was a vacuum tube receiver. I remember one stage was just a diode (tube or crystal, I don't remember) and hearing 30 hz
hum and then regenerative feedback through a triode tube and a complete superhetrodyne receiver. With boyish enthusiasm,
I thought the name superhetrodyne sounded really cool. This was with a hot soldering iron on a metal chasis.
The difficulty of the point to point wiring gave me a great appreication of printed circuts. I was barely able to follow the labs
and never did anything original. But, my dad who was an electrical engineer and worked for a decades later version
of the company David Sarnoff founded, RCA was proud of me.
reply
Santo
This brings back memories of my youth at about age12 to 14, when I first was introduced to crystal radios and transistors via a Remco toy kit. Never thinking to look in a book for answers, I too, rearranged the circuits and experimented for many hours, trying different configurations. I built an AM transmitter and then experimented with increasing its power and range. It was so exciting. I'm glad I never thought to look in a book because learning it on my own was much more fun, even though I didn't know exactly what I was doing.
I can really identify with Armstrong's excitement and how ecstatic he must have felt. This was a nicely told story. Thanks.
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This brings back memories of my youth at about age12 to 14, when I first was introduced to crystal radios and transistors via a Remco toy kit. Never thinking to look in a book for answers, I too, rearranged the circuits and experimented for many hours, trying different configurations. I built an AM transmitter and then experimented with increasing its power and range. It was so exciting. I'm glad I never thought to look in a book because learning it on my own was much more fun, even though I didn't know exactly what I was doing.
I can really identify with Armstrong's excitement and how ecstatic he must have felt. This was a nicely told story. Thanks.
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Pedro
Hmmm. I dont think there is a positive feedback here. It will be a positive feedback if the plate current or voltage is injected to the input grid. If that happens, there could be an oscillations and will distort the sound output. If the resistance of the wire from the filament to the negative terminal of the battery of the plate circuit is high, you could even have a negative feedback, for a lesser gain but wider bandwidth, unless you by-passed it with a capacitor to have more gain or larger amplification. But still, I admire the series of presentationsgood work!
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Hmmm. I dont think there is a positive feedback here. It will be a positive feedback if the plate current or voltage is injected to the input grid. If that happens, there could be an oscillations and will distort the sound output. If the resistance of the wire from the filament to the negative terminal of the battery of the plate circuit is high, you could even have a negative feedback, for a lesser gain but wider bandwidth, unless you by-passed it with a capacitor to have more gain or larger amplification. But still, I admire the series of presentationsgood work!
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Acme
Actually, at 4: 25 the grid must not be positive in relation to the filament. If it is, it attracts electrons like the plate. If the grid is at zero volts then it has no effect on the electrons flowing to the plate. The grid must be negative, to reduce the electron flow to the plate to a manageable level and thus a small change in negative grid voltage controls a large change in plate current. Thus the audion (vacuum tube) amplifies the weak signal. Thanks for the great video.
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Actually, at 4: 25 the grid must not be positive in relation to the filament. If it is, it attracts electrons like the plate. If the grid is at zero volts then it has no effect on the electrons flowing to the plate. The grid must be negative, to reduce the electron flow to the plate to a manageable level and thus a small change in negative grid voltage controls a large change in plate current. Thus the audion (vacuum tube) amplifies the weak signal. Thanks for the great video.
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DIMENSION
Mahalo Cathy well done. As a general class amature radio Ham I truly thankyou for this simple explanation. These coil and caps are also known as Tank Circuits. I have a trusty MFJ antennae tuner when you look inside you see a spring (coil) and the rotary capacitor. The coil looks kinda like a valve spring pretty thick, with taps at various points. These tank circuits made the under sea telegraph work and soon wireless. Mahalo Cathy! WH6DSF
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Mahalo Cathy well done. As a general class amature radio Ham I truly thankyou for this simple explanation. These coil and caps are also known as Tank Circuits. I have a trusty MFJ antennae tuner when you look inside you see a spring (coil) and the rotary capacitor. The coil looks kinda like a valve spring pretty thick, with taps at various points. These tank circuits made the under sea telegraph work and soon wireless. Mahalo Cathy! WH6DSF
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Lawrence
10: 11 This idea of using radio waves to broadcast music to the general public was a roaring success. Ironically, an earlier inventor had the idea of using his (wire-based) signal-transmission technology in exactly the same way, but that turned out to be a flop. For some reason he couldnt fathom, people preferred to use his invention to _talk_ to each other, rather than listen to music.
Can you guess whom, and what, I am talking about?
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10: 11 This idea of using radio waves to broadcast music to the general public was a roaring success. Ironically, an earlier inventor had the idea of using his (wire-based) signal-transmission technology in exactly the same way, but that turned out to be a flop. For some reason he couldnt fathom, people preferred to use his invention to _talk_ to each other, rather than listen to music.
Can you guess whom, and what, I am talking about?
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John
I actually made an Armstrong oscillator receiver that I saw in a magazine full of electronics projects. It uses one tube which is a pentode an this vacuum tube performs amplification, and detection of the radio signal, and it is very sensitive. The power source is batteries-i. e. an assortment of 9-volt and 3-volt batts. I had a lot of fun making it and listening to distant am broadcasts!
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I actually made an Armstrong oscillator receiver that I saw in a magazine full of electronics projects. It uses one tube which is a pentode an this vacuum tube performs amplification, and detection of the radio signal, and it is very sensitive. The power source is batteries-i. e. an assortment of 9-volt and 3-volt batts. I had a lot of fun making it and listening to distant am broadcasts!
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Robert
Kathy. I think your videos are great. However, you are implying that feedback is just an electrical thing. It was used in governors to control the speed of steam engines and hydraulic turbines long before electronics came along. Generally positive feedback was seen as a bad thing because it caused instability. I just had to get my 2 cents in. Keep up the good work.
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Kathy. I think your videos are great. However, you are implying that feedback is just an electrical thing. It was used in governors to control the speed of steam engines and hydraulic turbines long before electronics came along. Generally positive feedback was seen as a bad thing because it caused instability. I just had to get my 2 cents in. Keep up the good work.
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jrb
Hi Kathy - your diagram shown starting at 08: 20 does NOT illustrate feedback, either negative or positive, and your voice over isn't a clear explanation, but makes a number of errors. I fear that naive students may not get the point you are trying to make. It would help, for instance, if you explicitly included the battery providing power to the wing circuit.
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Hi Kathy - your diagram shown starting at 08: 20 does NOT illustrate feedback, either negative or positive, and your voice over isn't a clear explanation, but makes a number of errors. I fear that naive students may not get the point you are trying to make. It would help, for instance, if you explicitly included the battery providing power to the wing circuit.
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Bob
With all due respect saying that someone invented positive feedback is as dumb as kids who say Sir Isaac Newton invented gravity. Neither statement is true. Positive feedback has pre-existed in nature ALWAYS. Just like gravity.
Armstrong discovered A way to USE positive feedback constructively. Rare for positive feedback, but he didn't invent it!
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With all due respect saying that someone invented positive feedback is as dumb as kids who say Sir Isaac Newton invented gravity. Neither statement is true. Positive feedback has pre-existed in nature ALWAYS. Just like gravity.
Armstrong discovered A way to USE positive feedback constructively. Rare for positive feedback, but he didn't invent it!
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Sudarshan
Anyone who does not Express creates confounding uncertainty is one thing. One who does that know the power of dare to think and gaining from any video. The ZEAL to tell and make new generation aware of history, pain and gains are evident here as love for most dry subjects is daring adventure and thanks for that.
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Anyone who does not Express creates confounding uncertainty is one thing. One who does that know the power of dare to think and gaining from any video. The ZEAL to tell and make new generation aware of history, pain and gains are evident here as love for most dry subjects is daring adventure and thanks for that.
reply
Robert
Very good intro to the history and physics of radio, some errors explaining regeneration, no mention of tickler feedback coil. I have a Crosley pup which is a near copy of the original circuit Armstrong designed
I met Jeanne Hammond, Armstrong's niece at a RCA Radio Club of America banquet in NYC 1990's
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Very good intro to the history and physics of radio, some errors explaining regeneration, no mention of tickler feedback coil. I have a Crosley pup which is a near copy of the original circuit Armstrong designed
I met Jeanne Hammond, Armstrong's niece at a RCA Radio Club of America banquet in NYC 1990's
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drlegendre
Vacuum triodes are rarely ever operated with positive grids. The electron flow is controlled by making the grid more or less negative, without transitioning into the positive.
If the grid becomes positive, the tube enters grid current operation, with an associated sharp change in the tube's behavior
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Vacuum triodes are rarely ever operated with positive grids. The electron flow is controlled by making the grid more or less negative, without transitioning into the positive.
If the grid becomes positive, the tube enters grid current operation, with an associated sharp change in the tube's behavior
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wouldnt
I don't think you can say positive feedback is an invention. Maybe intentional positive feedback as a design element/technique in a particular circuit might be an invention. But positive feedback occurs in all kinds of naturally occurring phenomenon. Its a mathematical concept.
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I don't think you can say positive feedback is an invention. Maybe intentional positive feedback as a design element/technique in a particular circuit might be an invention. But positive feedback occurs in all kinds of naturally occurring phenomenon. Its a mathematical concept.
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tadonplane
Edwin Howard Armstrong is one of the greatest inventors of all time, yet hes hardly known by the public at large. His name can easily stand with Franklin, Davy, Watt, Otto, Diesel, Tesla, Edison, the Wrights, Goddard or anyone else whos ever invented anything!
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Edwin Howard Armstrong is one of the greatest inventors of all time, yet hes hardly known by the public at large. His name can easily stand with Franklin, Davy, Watt, Otto, Diesel, Tesla, Edison, the Wrights, Goddard or anyone else whos ever invented anything!
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Lawrence
5: 04 Heres a question: I recall the older (and now deprecated) name for a capacitor was a condenser. Why did it initially have that name? Was this another of those hangovers from the 19th-century history of (mis)understandings of the nature of electricity?
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5: 04 Heres a question: I recall the older (and now deprecated) name for a capacitor was a condenser. Why did it initially have that name? Was this another of those hangovers from the 19th-century history of (mis)understandings of the nature of electricity?
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Pete
Errm, the patent Pupin sold for lots of money - was the 'loading coil' which made long-distance telephones possible? That idea was invented by Oliver Heaviside. Pupin offered Heaviside a share of the profit, Heaviside refused as he wanted sole credit.
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Errm, the patent Pupin sold for lots of money - was the 'loading coil' which made long-distance telephones possible? That idea was invented by Oliver Heaviside. Pupin offered Heaviside a share of the profit, Heaviside refused as he wanted sole credit.
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jonahansen
I think the quote attributed to Armstrong is actually originally from Mark Twain:
It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.
But Nevertheless a good one that bears repeating!
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I think the quote attributed to Armstrong is actually originally from Mark Twain:
It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.
But Nevertheless a good one that bears repeating!
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Sumona
When I was a teenager I just connected a small wire to the grid of a vacuum tube with a current meter in the plate circuit. To appreciate how sensitive the gird is merely walking around the room would changed the plate current greatly.
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When I was a teenager I just connected a small wire to the grid of a vacuum tube with a current meter in the plate circuit. To appreciate how sensitive the gird is merely walking around the room would changed the plate current greatly.
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NO
So that was the superregenarative receptor. One valve.
Then came the superheterodyne wich mixed a local oscilator to get 455khz. Then amplify. detect and so on
Kathy will explain it better and with pictures. great hostory
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So that was the superregenarative receptor. One valve.
Then came the superheterodyne wich mixed a local oscilator to get 455khz. Then amplify. detect and so on
Kathy will explain it better and with pictures. great hostory
reply
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