Learning electronics tutorials for beginners is the primary goal of this site.
If you are new to electronics, I suggest to continue reading this page. You can also check out…
- 001 Resistive component multimeter voltage-current-resistance measurements
- Short learning electronics videos with diagrams collection – Page 1
- Circuit schematic collection 001 Basic components in series and parallel
- Electronic diagrams collection 001
- Brief circuit schematics with short video – List of pages
Some of the most commonly used schematic symbols are shown above. Sometimes analysis (voltage/current notation) will be also be added.
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Art of electronics is my favorite book!
- Circuits: Both ends (positive and negative) of a power supply/voltage source needs to be attached to a load that does something. Current flows equally in and out of all components and the power supply of a series circuit. All of the series components will limit the current more or less, based in the voltage they drop and or their resistance. Parallel components/power supplies share the current, but not necessarily equally.
- Avoid short circuits!: Don’t connect power supply + and – terminals directly together. That is called a short circuit. Too much current will flow if there is no short circuit protection of some kind.
- Light bulbs have resistance that limits current to a safe amount for it as long as the voltage applied to it is not too high. While limiting current they heat up enough to produce light. Their wattage (W/P) rating tells you how much current will flow through them based on their rated voltage. A 12V 12W light bulb will have 1A of current flowing through it. P = IV = 1A x 12V = 12W .
Diagram used in that video and links to the following topics covered more quickly than on this page is at 001 Resistive component multimeter voltage-current-resistance measurements
Kit that has everything you need to learn basic electronics and Arduino.
- LEDs produce light more directly from current but do not have much resistance unless specially made. So a series resistor is almost always used to limit current to below 20mA for most LEDs. LEDs must be forward biased to pass current and light up, which means that their Anode is more positive than their Cathode. While forward biased, it still takes a minimum voltage (forward voltage) before it will let current flow. The exact voltage varies between LEDs, but it is usually about a minimum of 1.5 volt to 2.5 volt (1.5V-2.5V). Reverse biased(RB) LEDs (Cathode more + and Anode more -) never light up, and if their RB breakdown voltage is exceeded, they will be destroyed.
Resistors have resistance, given in units called ohms (symbol Ω). Don’t test out the following example unless you have a 2 watt resistor (most are 0.25W maximum, 0.125W or less recommended): 1V across 1Ω of resistance results in 1A (one amp) of current. I = V/R (current equals voltage divided by resistance) is the Ohms law for current.
The schematic symbol for a resistor is commonly a zigzaging line, but can also be a rectangle. A suggested or commonly used value is usually written next to it as well. On each end of the resistor will be a schematic symbol for another component/power supply that you attach to one side of the resistor.
- Power/Watts: In the 1V/1Ω = 1A example above, the 1Ω resistor will have 1V across it and 1A of current flowing through it. The heat/power generated by the resistor will be 1V x 1A = 1W (one volt times one amp equals 1 watt), which means it should be at least a 2 watt resistor exposed to room temperature air to safely dissipate the heat generated. Most resistors are rated for 1/4W (0.25W) and should be limited to no more than 1/8W (0.125W).
- 1kΩ resistor: 1,000 ohms (1kΩ) is a nice resistance to start off with studying in electronics because 1V/1,000Ω = 0.001A, which is 1 milliamp (1mA) of current. Most current in basic electronics is in the mA range because an amp is a large amount of current for most circuits. For each volt across a 1kΩ resistor, you will get 1mA of current. So, 5V across a 1kΩ resistor will pass 5mA of current through it, which is safe because 5V x 0.005A = 0.025W, which is very safe for a 1/4W resistor (see above).
Power supply I use in my videos.
Resistor protecting an LED
- Resistors provide resistance and come in many fixed or adjustable values. They are generally used to limit current or divide up voltage.
For examples and demonstrations of voltage dividers check out: 004 Voltage dividers-trimpot-LDR light dependent resistor-fixed resistor
Many components need to be protected from the current that a voltage source can provide, and a resistor is commonly used to protect them.
There needs to be a voltage across the resistor for current to flow. The current that flows through it will also be the current that flows through series components (such as an LED), wires, and the power supply.
Similar resistor kit to the one I have. Lots of values at a low price.
In the diagrams above, a red LED is being protected by a 470Ω (ohm) resistor from a 9V battery that is powering it on a prototype breadboard. Forward biased red LEDs typically drop about 2 volts from reaching the resistor, which then has about 7V across it. 7 volts divided by 470Ω equals about 0.0149 amps (A) aka. 14.9 milliamps (mA) of current flowing through the resistor, LED, the battery and all other conductive parts of the circuit.
Now is a good time to move on to the next page if these topics are starting to get dull: Page 2 capacitor basics – How to use in circuits for DIY beginners learning electronics
LEDs are a type of diode (light emitting diode)
LEDs (light emitting diodes) are a type of diode. Diodes are the simplest semiconductor which have the basic property of conducting current easily in one direction while not conducting current in the opposite direction.
I love my kindle fire! I can read books and watch movies anywhere I go.
If diodes were perfect (ideal), then they would conduct current freely whenever a voltage is applied forward biased. They would also completely block current, no matter the voltage, while reverse biased. Of course, diodes are not perfect, so a certain forward voltage is needed (and dropped from the circuit) to conduct while forward biased. And, only so much voltage can be blocked while reversed biased before breakdown occurs.
- Rectifier diode: If you you really want a diode that blocks current well when voltage is applied reverse biased, and that passes current fairly easily while forward biased, then you want a rectifier diode. 1N4001 is a common rectifier diode that is included in many kits. Don’t use an LED for rectification unless there’s a specific reason why, and you sure to not exceed it’s relatively low breakdown voltage, which I don’t think is much more than 9V based on my earlier testing. Always look up the datasheet for the particular rectifier diode’s part number that you are interested in, to see it’s breakdown voltage.
- Schottky diode: Has a lower forward voltage than most rectifier diodes and still block a nice amount of voltage while reverse biased. Again, as always, consult the datasheet for specifics of the particular part you are interested in.
White version of the oscilloscope that I use in many of my recent videos.
Ohms law relationship of Voltage/Current/Resistance
Voltage = Electrical pressure. The force that is needed to move electric current. One side of a DC voltage source is positive while the other side is negative. Those 2 points have a voltage difference. A 9 volt alkaline battery has about a 9 volt (depending on how charged it is) difference between it’s positive and negative terminals. The negative terminal is typically called the 0V reference point or ground, while a 9V battery’s positive terminal is typically considered to be at 9 volts. So there’s a 9V difference between 0 and 9V. – Unit: Volts – Symbol: V
Breadboard that I use. I really like it! I’ve damaged a few holes but it has lasted a lot longer, and the components insert better, than the cheap boards I’ve used.
Current = Moving charges. Traditionally imagined as being a positively charged fluid going from more + to more -, and called conventional current. We still talk about current through a circuit in this way.
Electron flow is what actually moves through a circuit. Electrons flow from more negative to more positive, and when studying what electricity is actually doing at an atomic level, you must use electron flow. – Unit: Ampere (Amp) -Symbol: A or I. Remember that a capital i looks like a lowercase L in many fonts.
TO-220 component heat sinks used in a few of my videos. Helps quite a bit.
It helps to imagine electrical voltage as being similar to water pressure, while electrical current is similar to water flow.
Resistance = The opposition to current flow. Resistive components allow a certain about of current to flow through them based on their resistance and the voltage across them – I = V/R. This mathematical relationship is called Ohms law. -Unit: Ohms – Symbol: Ω (greek letter omega) or R
Power = Work done. When powered, components heat up, motors spin, LEDs emit light, etc.
The degree to which they consume power (P) depends on the voltage (V) across them and the current (I) running through them. This is usually calculated by the formula P = VI which is spoken as being “Power equals voltage times current”.
I really like this easy to use 8 battery universal charger. Made a few videos with it.
Updated kit of what I have. An assortment of commonly used integrated circuits (IC). I made a lot of videos with them.
In video below:
- Breadboard with 5V applied at the power rails.
- Normally open (NO) push button switch: It is off until you press it, which closes the switch and turns it on.
- LED: current must be limited to 20mA or less for most LEDs. They usually don’t get all that much brighter at 20mA than 15mA, so there’s usually no need to try to get 20mA.
- Resistor: For 5V, a 220Ω resistor in series with LED limits current to less than 20mA and keeps the resistor heat generation under 1/8W, which is recommended for the most commonly available 1/4W resistor. for 9V supply I use at least 470Ω and for 12V supply I use at least a 1,000Ω (1kΩ) resistor.
Screwdriver set that I use in my videos.
Nice looking LED kit. Good to have a lot of LEDs because it’s relatively easy to damage them, or to want to use a lot of them in various projects.
Using LEDs to “see” polarity
Since LEDs only light up in one direction (forward biased), they can be wired in parallel while also being wired in opposite directions of each other. The 2 of them still need to be connected in series with a protective resistor. Applying a voltage in either direction will light up the forward biased LED only.
The ad above is to a best selling multimeter since the ones I use are unfortunately not being sold anymore. It still helps this site if you click the link, check out the meter and compare it with other meters to see what looks best for you!
Updated version of one of my favorite multimeters. It has some oscilloscope capabilities.
A lot of the components that I use are in this diode and transistor semiconductor kit.
Nice looking larger value capacitor kit.
The ad above is where I got my LCR meter. It is not a replacement for a multimeter, but is a nice additional meter for getting more info about inductor, capacitor and resistor components than you can get from a standard multimeter.
Portable solar panel with 5V USB output. I find it better to use the panel to charge a portable power bank, which can then be used to charge a cell phone, than to try to charge a cell phone directly.
One of my favorite portable power banks, this one has a better display than my version.
Really easy to use USB multimeter tester used in a number of my videos.
Some nice low power boost converters above that I enjoyed using in a couple videos.
Don’t have this buck converter, but it looks nice.
My 74LS00 series IC kit (assuming they haven’t changed it at all)
74HC00 kit that is similar to mine, which isn’t available anymore. List of included IC’s is shown in the images.
4000 series IC kit I have (assuming they don’t changed part numbers)
- Information on this site is not guaranteed to be accurate. Always consult the manufacturer info/datasheet of parts you use. Research the proper safety precautions for everything you do.
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