Battery Resistor Capacitor capacitor voltage rises charging LED Flasher Learn timing, polarity, current limiting, and breadboard layout.
555 timer LEDs resistors capacitor
Build a small audio amp and understand gain, coupling, and noise.
LM386 module or IC speaker potentiometer capacitors
Solar panel Charge control Battery 5 V USB load sun current charge Solar Phone Charger Intermediate
Solar Phone Charger 50% Learn solar input, battery protection, boost conversion, and load limits.
Solar panel charge controller module battery pack USB boost module
Battery Switch Coil coil current Flyback diode later Electromagnet See magnetic fields from current and learn why coils need current limits.
Enamelled wire iron bolt low-voltage battery switch
Antenna Coil Capacitor LED Speaker RF signal Detector diode Crystal Radio Intermediate
Crystal Radio 54% Explore resonance, detection, antennas, and radio waves without a battery.
Coil variable capacitor diode high-impedance earphone
Two-Way Speaker Crossover + - tweeter + return woofer + balance polarity compare AMP low volume INPUT + / - CAP high-pass TWEETER highs COIL low-pass WOOFER lows L-PAD optional PHASE swap links Intermediate
Speaker Crossover 46% Split audio bands and learn how filters protect and shape speakers.
Capacitors inductors resistors speaker drivers
Adjustable Bench Supply + - IN+ OUT+ OUT- sense output cap DC ADAPTER 12-24 V FUSE input SWITCH DC rated DC-DC V/I limit REVERSE protect POSTS + / - DISPLAY sense Intermediate
Bench Power Supply 42% Create an adjustable low-voltage supply for electronics testing.
DC supply module enclosure terminals fuse
Battery Switch NPN Buzzer trigger Simple Alarm Circuit Beginner
Simple Alarm Circuit 74% Use a transistor as a switch and build a practical sensor circuit.
Buzzer transistor reed switch resistor
Beginner+
Bluetooth Stereo Speaker 66% Build a rechargeable stereo speaker while learning audio signal flow, shared grounding, charging, and bridge-tied speaker outputs.
Bluetooth receiver PAM8403 amplifier protected 18650 cell USB-C charger/protection board
Intermediate
Pocket GPS Trip Tracker 50% Build a portable coordinate logger that displays position and records timestamped trips to a microSD card.
ESP32 board GNSS receiver microSD module OLED display
Class-D Amplifier Board + VCC GND L/R line in signal gnd L+ / L- R+ / R- mute / standby DC SUPPLY 12-24 V FUSE input SWITCH power AUDIO L / G / R VOLUME stereo pot CLASS-D TPA3116 LEFT speaker RIGHT speaker Intermediate
Class-D Stereo Amp Board 40% Build a louder low-voltage stereo amplifier while learning fused power, line input, and bridge speaker outputs.
TPA3116 amp board DC adapter fuse switch
Audio Signal Tracer VCC GND signal wiper common ground audio out PROBE tip 100k series CAP DC block VOLUME 10k LM386 battery amp SPK listen 9 V switch CLIP ground Beginner+
Audio Signal Tracer 72% Build a repair tool that lets you follow audio through a circuit and find where it disappears.
LM386 amp probe tip input capacitor series resistor
Dummy Speaker Load + - 8 ohm 4 ohm pair measure thermal mount AMP output POSTS + / - MODE 4 / 8 ohm 8R 50W resistor 8R 50W resistor HEAT SINK vented case TEST POINTS AC volts Intermediate
Dummy Speaker Load 46% Test small amplifiers into a silent 4 or 8 ohm load and calculate output power safely.
Power resistors heat sink binding posts impedance switch
Capacitor ESR Comparator + - pulse test + return sense read discharge first 9 V battery OSC 555 pulse SENSE 1-10R CLIPS cap under test METER compare DISCHARGE button + R Intermediate
ESR Capacitor Checker 56% Compare electrolytic capacitors with a low-voltage pulse tool and learn what poor ESR looks like.
555 oscillator sense resistor test clips meter display
PWM Motor Controller + ground motor + motor - diode stripe PWM gate supply cap DC IN 6-12 V FUSE motor PWM 555/module GATE R + pulldown MOSFET low side MOTOR brushed DC FLYBACK diode Intermediate
PWM Motor Controller 50% Control a small DC motor speed while learning MOSFET switching, flyback protection, and current paths.
555 PWM module logic MOSFET flyback diode fuse
Portable Buck/Boost Pack B+ B- OUT+ ground bus switched + 5 V variable voltmeter 18650 protected CHARGER B / OUT FUSE 1-2 A SWITCH main BOOST 5.0 V ADJUST set rail OUT ports Intermediate
Buck/Boost Power Pack 56% Build a portable regulated power box for small electronics projects.
Protected 18650 cell USB-C charger/protection board fuse switch
Relay Timer Controller VCC GND trigger timing RC output coil - coil + clamp NO contact load supply DC IN 5-12 V TRIGGER button/sensor 555 TIMER delay DRIVER BJT/MOSFET RELAY coil + contacts FLYBACK stripe to + DC LOAD fan / LED Beginner+
Relay Timer Controller 60% Switch a low-voltage load for a timed interval while learning relay coils, drivers, and contact wiring.
555 timer relay transistor or MOSFET flyback diode
