Supplier product photo
Build an infinity light cube
Listing specifies 5-volt direct current. Soldering required; battery and glue not included.
First Spark · Tricky Circuit
Learn electronics from zero
54 interactive electronics lessons, 162 challenges and three difficulty levels in eleven languages. Learn how components interact through experiments and a searchable Circuitpedia.
First circuits
Read the world
Control a circuit
- 12
A one-way gate for current
D + R
- 13
A small signal takes control.
NPN + LED
- 14
Dim a light by switching quickly
Pulse width and average current
- 15
Switch a load with an electric field
Gate, source and drain
- 16
A diode that holds a voltage
Zener clamp and current budget
- 17
Build a decision with two switches
The NAND logic gate
Signals and time
- 18
Catch time in a circuit.
Resistor + capacitor
- 19
Turn a voltage into a number
Resolution and quantization
- 20
Let slow changes pass
A resistor–capacitor low-pass filter
- 21
Let fast changes through
A resistor–capacitor high-pass filter
- 22
A coil resists sudden current changes
Magnetic energy in an RL circuit
- 23
Tune a circuit like a musical note
Resonance in a series RLC circuit
- 24
Make a timer blink by itself
The 555 astable oscillator
- 25
Give one press a timed response
A 555 monostable pulse
Combine your skills
- 26
Protect a divider from its load
A voltage-follower buffer
- 27
Amplify a signal and flip it
An inverting operational amplifier
- 28
Make a small signal taller
A non-inverting operational amplifier
- 29
A night-light that remembers
Light sensing and hysteresis
- 30
Turn both halves of a wave upright
A four-diode full-wave bridge
Decisions and memory
- 31
A voltage that makes a decision
Comparator: below, equal, above
- 32
A decision that remembers
Schmitt trigger and two thresholds
- 33
The coil keeps going after switch-off
Relay coil and its flyback diode
- 34
Teach a circuit to remember
A one-bit SR latch
- 35
Turn four bits into a voltage
A four-bit R–2R DAC
- 36
Count events with four lights
A binary counter and clock divider
Logic that calculates
- 37
Spot the difference with XOR
The gate that notices disagreement
- 38
Make a tiny binary calculator
Half adder: sum and carry
- 39
Pass the carry to the next place
Full adder: three inputs, two answers
- 40
Choose which signal gets through
MUX: a controlled crossroads
- 41
Turn an address into one chosen line
Two-bit decoder and one-hot output
- 42
Add one bit to spot some errors
Even parity and its blind spot
Analog signal workshop
- 43
Mix two signals with resistors
An inverting summing amplifier
- 44
Keep the difference, reject the shared part
A matched difference amplifier
- 45
Let voltage accumulate with time
An inverting integrator
- 46
Measure how quickly a signal changes
A ramp differentiator
- 47
Freeze a measurement, then watch it fade
Sample and hold with passive leakage
- 48
Detect the safe middle
A window comparator
Motion, sound and communication
- 49
Steer a shaft with time
Servo: a tiny timing command
- 50
Turn counted steps into motion
Stepper: commands with a direction
- 51
Build a tone from two levels
Frequency, pulse shape and pitch
- 52
Measure with an echo
Ultrasonic time of flight
- 53
Notice a tiny resistance imbalance
The Wheatstone bridge
- 54
Turn a byte into a timed message
UART: an 8N1 frame
EXPERIMENT BENCH
Change the circuit settings, predict the readings, then check a challenge. These are learning models, with the assumptions explained in each lesson.
Sign in to save progress. Guest progress stays on this device.
