Main implementations: the same as electronic switches: vacuum tubes in the past, and transistors in the second half of the 20th century.
How to make an LM386 audio amplifier circuit by Afrotechmods (2017)
Source. Builds the circuit on a breadboard from minimal components, including one discrete transistor. Then plays music from phone through headset cables into a speaker.This is how electronic circuits are normally prototyped!
Once you validate them like this, the next step is usually to move on to printed circuit boards for more reliable production setups.
Breadboards are a thing of beauty and wonder.
Point-to-point constructions on woden boards
. Source. Predecessors to breadboards from where the name came. A thing of beauty, so vintage. You could actually write stuff on those with a pencil!Breadboards - Trash or Treasure? by Keysight (2020)
Source. Ciro Santilli's hardware ELEGOO Upgraded Electronics Fun Kit Updated 2025-04-24 +Created 1970-01-01
2022-10 ELEGOO Upgraded Electronics Fun Kit www.elegoo.com/products/elegoo-electronics-fun-kits-4-versions Manuals:
Breadboard power supply module MB‐V2:
TODO center positive or center negative?
Does not come with AC adapter, getting this one: www.amazon.co.uk/dp/B08ZN476FW output: DC 9V 1A Power Supply Adapter, Plug 5.5mm x 2.1mm, Center Positive,B rand: Security-01, input: AC 100-240V 50/60 Hz, Cable length: 1.8m
- youtu.be/eYVOdlK15Og?t=66 RC oscillator on breadboard. Produces rectangular wave. Mentions popular integrated circuit that does it: 555 timer IC.
- youtu.be/eYVOdlK15Og?t=175 LC oscillators allows for higher frequencies. Produces sinusoidal output on MHz range. Uses an amplifier to feed back into input and maintain same voltage. Hard to make reliably on breadboard.
- youtu.be/eYVOdlK15Og?t=315 crystal oscillator. Mentions it acts like an LC oscillators. Shows and equivalent model. Wish he had talked more about them. You need support components around it: similarly to the LC case, the amplifier is generally not packaged in.
When Ciro Santilli was studying electronics at the University of São Paulo, the courses, which were heavily inspired from the USA 50's were obsessed by this one! Thinking about it, it is kind of a cool thing though.
That Wikipedia page is the epitome of Wikipedia failure to explain things in a way that is of any interest to any learner. Video 1. "Tutorial on LC resonant circuits by w2aew (2012)" is the opposite.
Tutorial on LC resonant circuits by w2aew (2012)
Source. - youtu.be/hqhV50852jA?t=239 series LC circuit on a breadboard driven by an AC source. Shows behaviour on oscilloscope as source frequency is modified. We clearly see voltage going to zero at resonance. This is why thie circuit can be seen as a filter.
- youtu.be/hqhV50852jA?t=489 shows the parallel LC circuit. We clearly see current reaching a maximum on resonance.
Introduction to LC Oscillators by USAF (1974)
Source. - youtu.be/W31CCN_ZF34?t=740 mentions that LC circuit formation is the root cause for Audio feedback with a quick demo. Not very scientific, but cool.
LC circuit by Eugene Khutoryansky (2016)
Source. Exactly what you would expect from an Eugene Khutoryansky video. The key insight is that the inductor resists to changes in current. So when current is zero, it slows down the current. And when current is high, it tries to keep it going, which recharges the other side of the capacitor.Testing and Circuit for a Condenser microphone by RSD Academy (2018)
Source. Not very numerical, but shows a simple working breadboard circuit and an oscilloscope. He whistles with his mouth to get a pretty pure frequency.
That type of microphone requires a bias voltage. The circuit is in Ciro's ASCII art circuit diagram notation:
DC_9---R_10k--+--MICROPHONE--+--G
| |
+-------V------+
Soundwaves on an oscilloscope by Animated Science (2015)
Source. Dude speaking to microphone. Some analysis of how different sounds look like. No circuit diagram.The breadboard of photonics!
For example, that is how most modern microscopes are prototyped, see for example Video "Two Photon Microscopy by Nemonic NeuroNex (2019)".
This is kind of why they are also sometimes called "optical breadboarbds", since breadboards are what we use for early prototyping in electronics. Wikipedia however says "optical breadboard" is a simpler and cheaper type of optical table with less/no stabilization.