ElectronicsNotes by Ian Poole
@ElecNotes
Followers
6,711
Following
215
Media
7,650
Statuses
16,188
Clear summaries, information & videos about electronics, radio & connectivity by Ian Poole
South East, England
Joined November 2016
Don't wanna be here?
Send us removal request.
Explore trending content on Musk Viewer
#Mchoice2024
• 249004 Tweets
Ganesh Chaturthi
• 154881 Tweets
ホームラン
• 64991 Tweets
#マイナビTGC
• 64939 Tweets
ビッグラン
• 19295 Tweets
三千院帝
• 14836 Tweets
九能帯刀
• 14678 Tweets
クリスマスパレード
• 13362 Tweets
#AlonAlbumTracklist
• 11098 Tweets
#PABLOAlonAlbum
• 10736 Tweets
Understand the Impedance of Coax Cables
All feeders possess a characteristic impedance. For coaxial cable there are two main standards that have been adopted over the years. These are 75 Ω and 50 Ω.
The 50 Ω coax cable is used for professional and commercial applications
9
71
480
Understanding OFDM - Orthogonal Frequency Division Multiplex
OFDM is a form of multicarrier modulation. An OFDM signal consists of a number of closely spaced modulated carriers.
One of the issues with any radio signal is that the side bands generated by the modulation spread
3
47
295
How to Transistor Schmitt Trigger Circuit
It’s very easy to design a Schmitt trigger circuit using just two transistors.
It incorporates the concept of the two switching transition states by applying positive feedback within the circuit.
The actual hysteresis within the
4
29
221
How to Design a Common Emitter Transistor Amplifier Stage in 10 Easy Steps
The common emitter transistor amplifier is one of the most common types of amplifier.
It is often used in its AC coupled format to amplifier audio or many other types of signal.
The design is relatively
5
35
206
Schottky Diodes are Supposed to have Advantages, but where are they Used?
The Schottky barrier diodes are widely used in the electronics industry finding many uses as diode rectifier.
Its unique properties enable it to be used in a number of applications where other diodes
2
33
204
Understanding Tropospheric Enhanced Conditions: Lifts, Ducting, Tropo
Under certain conditions the radio propagation conditions provided by the troposphere are such that signals travel over much greater distances than normal.
This enhanced tropospheric refraction occurs when
4
36
198
Should you use an op-amp chip as a comparator?
Op-amps can seem like a very good option as a comparator if super fast operation is not needed, but is this wise?
Whilst it is easy to use an operational amplifier as a comparator, especially when it may be easy to use one if a
4
24
194
Radio Signal to Noise S/N Ratio, SNR Explained
The signal to noise ratio, SNR, S/N, is used to define the sensitivity performance of radio communications equipment particularly at HF. It uses a simple formula to calculate the SNR.
Signal to noise ratio defines the difference
2
49
194
RF Mixer Types Explained
There are several different types of RF mixer and often the terminology used can be a bit confusing.
My summary of the different types reveals what they are and their differences.
One way in which RF mixers are described is in terms of the type of
0
22
189
The transistor capacitance multiplier circuit can be very useful in many overall designs.
Check it out:
#circuitdesign
#transistor
#capacitancemultiplier
1
23
186
The Yagi is one of the most popular directional antennas used for everything from TV reception to data links, HF radio & more. Understand what it is & how it works
#antennas
#Yagi
#amateurradio
#hamradio
#hamr
2
26
171
Transistor Foldback Current Limiting Circuit
The foldback current limiting circuit gives far better performance than the ordinary constant current limited used in the more basic power supply applications.
But it always seemed a bit like magic to me because it suddenly reduced
3
16
170
Log Periodic Dipole Antenna Explained
Log periodic antennas are very useful because they have a wide bandwidth - often as high as 4:1.
The basic log periodic dipole array consists of a number of dipole elements. These progressively reduce in size from the back to the front –
2
26
168
Understand the various aspects of antenna resonance and bandwidth and how they are linked.
#antennas
#resonance
#bandwidth
#hamradio
#hamr
#amateurradio
3
24
164
Understand the design of a two transistor Schmitt trigger circuit: design, how it works, calculations, hints & tips.
Discover now:
#transistor
#schmitttrigger
#circuitdesign
0
27
154
This simple one transistor high pass filter can be useful in a number of circuit designs. Find out about the circuit, calculations, etc . .
Check it out now:
#highpassfilter
#circuitdesign
#transistor
1
30
156
Simple SWR Meter Circuit - Reflectometer
The SWR meter is an electronic test instrument that provides a good indication of the level of standing wave ratio present in a feeder.
Often these SWR bridges are left in circuit as a continuous indication of the antenna system
2
25
155
Understand Op-Amp Notch Filter Circuit Design
Notch filters are very useful when single frequencies need to be removed. op-amp circuits are very easy to design.
Discover now:
2
12
154
How does RF mixing work?
Sometimes it may be difficult to visualise how an RF mixer or multiplier works.
Essentially the instantaneous values of the two inputs are multiplied together.
Some years ago when I used to chat with a friend at work over our lunch break we would try
3
21
155
What is Antenna Resonance?
Radio antennas have a bandwidth over which they can operate effectively; even wideband antennas.
Many antennas operate in a resonant mode and this gives them a relatively narrow bandwidth over which they are able to provide excellent performance.
An
3
23
151
Difference between RF network analyzers and spectrum analyzers
Although there are many similarities between RF network analyzers and spectrum analyzers, there are also several major differences, especially in the types of measurements that are made.
In particular they make very
1
27
150
A great post about Smith charts, what they are and how they can be used in RF design.
The Smith Chart: Its History and Why It’s So Important for RF Designers
Read more:
1
52
269
0
22
149
2
28
137
Understanding Antenna Feed Impedance
The feed impedance of an antenna is a very important aspect of its operation.
It consists of both resistive and reactive constituents.
Antenna feed impedance resistive elements:
The resistive elements are made up from two constituents.
2
20
138
FET Circuit Configurations Explained
Understand the basics of the different circuit configurations used for FET circuit design.
There are three types mirroring those used with bipolar transistors and vacuum tubes / thermionic valves.
They are common source, common drain and
2
16
138
Electromagnetic waves – what are they
Electromagnetic waves or e/m radiation has two constituents. The radiation is made from electric and magnetic components that are inseparable.
The planes of the fields are at right angles to each other and to the direction in which the wave
3
25
135
How to design a simple common emitter transistor amplifier: step by step instructions.
#circuitdesign
#commonemitter
#transistorcircuit
1
32
133
The Yagi is one of the most popular directional antennas used for everything from TV reception to data links, HF radio & more. Understand what it is & how it works
#antennas
#Yagi
#amateurradio
#hamradio
#hamr
0
34
130
The inverting amplifier is one of the most useful op-amp circuits. Discover more . . .
#circuitdesign
#opamp
#amplifier
3
25
127
The common base transistor circuit configuration is used where a low input impedance is needed.
Find out now: …
#transistor
#circuitdesign
4
17
124
How Does a Phase Locked Loop Work?
The basic concept of the operation of the PLL is relatively simple, although the mathematical analysis and many elements of its operation are quite complicated.
The diagram for a basic phase locked loop shows the three main element of the PLL:
5
24
126
Online training courses about FPGAs could be a stepping stone to a new job, better responsibilities, or just keeping up with current technology.
Check out this great selection:
2
22
125
TCXOs Temperature Compensated Crystal Oscillators: what are they & how do they work.
TCXOs are used in many electronic circuit designs when a higher level of accuracy and stability is needed than is possible with a standard crystal oscillator.
Like all electronic components,
4
24
124
The batteries in my favourite old analogue multimeter have long gone obsolete.
Now I've found a 3D printed source and I've been able to get the meter going again on all ranges.
For many years, the 15V B121 battery has been impossible to source, now I've found someone who makes
3
15
122
1
21
115
Easy Way to Determine Bandwidth of an FM Signal. - Carson’s Rule.
The bandwidth of a frequency modulated, FM signal depends on a variety of factors including the level and frequency of the modulation, and their levels are important for broadcast and radio communications.
The
3
14
119
Simple but Effective Over-Voltage Protection Circuit
This crowbar over voltage protection circuit is rather crude in some ways, but it can be very effective in protecting expensive electronic circuits from damage in the event of a breakdown of a series regulator.
As the name
2
10
117
Simple transistor pulse generator circuit
It’s sometimes useful to be able to generate a short pulse from an incoming square waveform.
When one is needed it’s very easy to create a simple pulse generator circuit design using just two transistors and a handful of other
2
22
117
How does a thyristor work?
The way in which a thyristor operates is different to other devices. Normally no current flows across the device.
However if a supply is connected across the device, and a small amount of current is injected into the gate, then the device will "fire"
3
20
115
Voltage and Current on Radio Antennas
The current and voltage on any radiating element vary along its length, and this is true for the dipole as well as for any other antenna.
It’s important to understand because it can have an impact on the performance of an antenna.
The
3
21
115
Transistor Darlington Pair: the facts.
One transistor circuit configuration that can be used to very good effect in many instances is the Darlington Pair. The Darlington Pair offers a number of advantages.
In this the two collectors are tied together and the emitter of the
3
15
114
Check out how to design a voltage controlled oscillator for a phase locked loop, synthesizer, etc.
#RFdesign
#phaselockedloop
#VCO
#voltagecontrolledoscillator
2
23
112
How to Run Bipolar Transistors in Parallel
There can be issues to running two transistors in parallel, but if the circuit design is addressed correctly, then it can be achieved very successfully.
The problem revolves around sharing the current equally between the two devices.
2
18
112
How to Use Varactor Diodes in Oscillator Circuits
A varactor diode requires the reverse bias to be applied across the diode in a way that does not affect the operation of the tuned circuit of which it is part.
Care must be taken to isolate the bias voltage from the tuning
1
16
107
Laser diodes are different from standard light emitting diodes because they emit coherent light which can be used for many applications including reading data in CD drives, digital communications and much more.
Find out more:
0
33
104
The detection or demodulation of a frequency modulated signal is key to its use in radio communications.
Discover how this is achieved and the circuits used:
#frequencymodulation
#demodulation
#electronics
0
26
102
Free Space Path Loss and Frequency Dependence Explained
For a long time, I wondered about the frequency dependence of the free space path loss equation.
FSPL = (4 pi D / lambda )^2
According to this, the loss increases with frequency, but the light from distant stars is still
1
22
105
Understand the main causes of electromagnetic interference, EMI.
Discover now:
#EMI
#EMC
#electromagneticinterference
1
17
103
The Discone antennas is used because of its very wide bandwidth for many applications including scanning.
Understand its operation & performance:
#antennas
#AmateurRadio
#hamradio
#hamr
2
18
101
Simple two transistor pulse generator circuit design.
Check it out:
#circuitdesign
#pulsegenerator
#transistor
4
19
104
The Quasi Complementary Output Stage using Darlington and Sziklai Pair Configurations
One of the key challenges in many audio output stages, is to be able to have two similar devices, one for each half of the cycle.
One popular solution is the quasi-complementary symmetry
1
19
104
Transistor Capacitance Multiplier Circuit
The transistor capacitance multiplier can be used to give additional levels of smoothing in many areas of electronics.
The basic capacitance multiplier circuit is essentially a simple emitter follower with a capacitor on the base and a
1
16
103
We all use radio antennas, but how do they actually work & what are their properties?
Discover now:
#antennas
#amateurradio
#hamradio
#hamr
0
25
98
The Op amp Wien Bridge sine wave oscillator or generator is an excellent circuit for generating a sine wave signal at audio frequencies and above.
Find out now:
1
18
100
It is amazing quite what can be achieved using a single transistor circuit.
It is often useful to be able to have a simple one transistor active high pass filter circuit using only a few components and simple calculations for use in various electronic circuit designs.
Its often
0
18
99
Transistor Pulse Generator Circuit Design
It’s often necessary to create short trigger pulses from an incoming rectangular wave. Here’s how.
It is very easy to create a simple pulse generator circuit design using just two transistors and a handful of other electronic
1
9
97
Two pole low pass filter op-amp circuit design
The filter is straightforward, its design & implementation are easy and it provides a good overall 'sure-fire' solution.
The op amp circuit provides unity gain and a Butterworth response (the flattest response in band, but not the
3
17
97
Understanding the Log Periodic Antenna
The log periodic antenna often called the LPDA is a wideband directional antenna that provides gain and directivity combined over a wide band of frequencies.
The log periodic dipole array is the most common form of this antenna and it
1
26
98
The 7400 series logic chips were the mainstay of digital / logic design for many years. Discover more about them and their internal workings.
Find out now:
3
12
93
There are several different circuits that can be used to drive relays - some protection is required to prevent back EMF destroying devices.
Find out more:
#relay
#relayswitch
#electronics
#electroniccomponents
0
14
89
There are three different basic transistor circuit configurations, each with its own properties. Which is the right one for your design?
Discover now:
#transistor
#circuitdesign
#electronics
2
22
92
Transistor Common Emitter Amplifier
The common emitter amplifier configuration provides voltage gain and is one of the most widely used transistor configurations for electronic circuit design.
The common emitter transistor amplifier circuit is one of the mainstay circuits for
1
22
93
Step by step instructions on how to design a transistor common emitter amplifier stage - very basic circuits to the more advanced AC coupled stages.
Discover now;
0
20
93
Understand how frequency modulated, FM signals can be demodulated or detected.
Discover now:
#frequencymodulation
#RFdesign
#RFtechnology
#electronics
0
18
93
@Vanguard_WW2
War is a dreadful thing and not to be taken lightly. But it takes brave people to stand up to oppression, occupation and acts of aggression. For evil to take hold, all it takes is for good men to do nothing. Madeleine Riffaud did what she could. A brave woman.
2
5
93
Understand SWR - what it is and why it is important.
Standing waves are a fact on all antenna feeder systems.
To get the most from an antenna it is necessary to understand standing waves & their effects.
Discover what you need to know in my video:
0
18
93
Basic 78xx Voltage Regulator Circuits
The 78xx series. regulators have been a popular choice as a straightforward yet capable refit for many years.
Even though they have been around for a long time, they are still on the “active” or “current “ lists for many IC manufacturers.
4
10
94
Amplitude Modulation Explained
Amplitude modulation or AM, is a form of RF modulation used for radio transmissions for broadcasting and two way radio communication applications.
Although it is one of the earliest used forms of modulation, it is still used today, mainly for
3
12
93
What is a Gilbert Cell RF Mixer / Multiplier
The Gilbert cell RF mixer or multiplier is a form of RF mixer circuit that is widely used in integrated circuits. The circuit is able to provide excellent performance although it does require a larger number of components than many
1
7
91
We all use digital multimeters, but how exactly do they work? Discover now!
When looking at how a digital multimeter works, it is necessary to understand the core technologies that are generally used.
For the DMM, one of the key processes involved in this is that of the
4
15
89
The Art of Electronics must be the all-time great book for electronics engineers. Recently updated it is still the bible for electronic circuit designers.
Find out about it in our bookstore:
#books
#artofelectronics
0
16
88
Understanding X10 Oscilloscope Probe Compensation
X10 oscilloscope probes are widely used to enable a high impedance to be presented to the point under test. These probes do need adjusting or compensating if accurate results are to be obtained.
The X10 scope probe is
4
12
88
Triac Circuits - points to remember
Triacs are not the complete solution to all AC switching requirements. They may provide switch on both halves of the cycle, but they have their issues.
Triacs have some issues when they are used in various circuits, and these must be
1
15
89
RF resistive attenuator design explained: circuit formats, design equations, design guidelines - in fact all you need to know.
#RFdesign
#attenuators
#RFattenuator
#circuitdesign
1
11
86
Metal Oxide Varistor, MOV Explained
Varistors are a form of resistor in which the resistance changes significantly with the applied voltage.
As the resistance falls with increasing voltage, they are used to absorb transient spikes on incoming power and data lines.
The key
4
15
88
Antenna beam width, directivity, & gain explained: understand the link between gain and beam width or directivity.
#antennas
#gain
#beamwidth
#hamradio
#hamr
#amateurradio
1
17
85
Common Base Transistor Amplifier
In my previous posts I looked at the two most popular transistor circuit configurations. Now I’ll look at the common base one which can has some useful characteristics that can be used in a number of situations and circuits.
The common base
1
20
88
Why is 5/8 wavelength antenna so popular when a 3/4 wavelength would give a high current / low voltage feed point?
Discover now:
#antennas
#AmateurRadio
#hamradio
#hamr
#hamradiostuff
0
19
83
Understanding RF / Microwave Circulators & Isolators
RF or microwave circulators are typically three port devices based on ferromagnetic materials that steer RF power from one port to another, while isolating this power from the others and are therefore used in many mmWave,
1
14
87
Understanding RF Mixing / Multiplication: Frequency Mixers
RF mixers or frequency mixers use the process of RF mixing or multiplication.
This is totally different to the process of analogue addition that is used in audio mixers.
RF mixing or multiplication is key to many RF
3
19
85
NVIS Propagation: Near Vertical Incidence Skywave Explained
NVIS propagation, Near Vertical Incidence Skywave propagation is a form of radio signal propagation that is sometimes used on the MF and HF bands.
It can be used to provide radio communications and broadcasting
5
21
82
Thyristors Explained: what they are, what they do & how they work.
Thyristors or SCRs are widely used for various forms of power control.
It’s probably first worth looking at the structure.
It’s a rather an unusual form of component because it consists of four layers of
1
13
84
Understanding standing wave ratio: what is it & how does it affect radio stations.
Watch now:
#standingwaveratio
#AmateurRadio
#hamradio
#hamr
0
27
82
Top Tips for Zener Diode Circuit Design
Here are my top tips for designing circuits using Zener diodes.
These tips will help the circuit work first time, perform better, and will ensure you don’t fall into any design traps!
•Buffer the Zener diode circuit with an emitter or
5
16
83
Understand the main causes of electromagnetic interference, EMI.
Discover now:
#EMI
#EMC
#electromagneticinterference
0
30
83
It’s very easy to design a simple high pass filter using a single transistor.
Discover now:
#transistor
#highpassfilter
#circuitdesign
#electronics
0
16
80
Simple low pass filter with existing op-amp amplifier circuit.
If you don’t want to design a full two pole op-amp filter, it’s very easy to add some roll off to an existing amplifier.
The simplest op amp circuit for a low pass filter circuit simply places a capacitor across the
2
14
81
Where is AM used these days, or is it totally out of date.
Amplitude modulation is used in a variety of applications. Even though it is not as widely used as it was in previous years in its basic format it can nevertheless still be found.
•Broadcast transmissions: AM is
5
20
81
AM Demodulation Techniques Explained
There are a number of techniques that can be used to demodulate amplitude modulated, AM signals.
Different types are used in different applications to suit their performance and cost.
•Diode rectifier envelope detector: This form of
1
12
81
Top tips for transistor switch circuit designs
Transistor switching circuits are typically very easy to design, but sometimes a few precautions need to be observed if the circuit is to work effectively and reliably.
The pointers or hints and tips below have been learned the
2
10
81
RF / Microwave Circulator / Isolator Basics
RF or microwave circulators are often three port devices based on ferromagnetic materials that steer RF power from one port to another, while isolating this power from the others.
The connections to RF circulators are normally called
3
14
79
The transistor Darlington pair circuit configuration enables very high levels of current gain to be achieved.
Discover how it works & understand its characteristics:
#circuitdesign
#circuitdesignideas
#electronics
#electroniccomponents
2
5
78
The current mirror circuit is used in many circuit designs, especially within analogue ICs.
Discover more:
#transistor
#circuitdesign
#currentmirror
0
15
78
Foldback Current LImiter Circuits
Although constant current limiting circuits are very useful, they may not be adequate for all situations. When a fault occurs and drives the power supply into a condition where the maximum current is still delivered, it is likely that more
2
18
79
Understand what Doherty amplifiers are and why they are used in RF power amplifiers to improve efficiency.
Discover now:
#Dohertyamplfier
#RFdesign
1
18
75
A good RF antenna ground is essential for many antennas.
Check out our summary, practical guidance & tips to give you the best ground system.
#antennas
#hamradio
#hamr
#amateurradio
#RFground
2
17
78
Design of voltage controlled oscillators for phase locked loops (& PLL synthesisers) has a number of requirements.
Discover more:
#RFdesign
#phaselockedloop
#voltagecontrolledoscillator
#VCO
0
24
75
Transistor Relaxation Oscillator Circuit Explained
A very simple one transistor oscillator using a one transistor relaxation oscillator configuration to provide a continuous output. It's easy to implement, but it's not an elegant design, but useful in some instances.
It's a
6
9
78