Electronic toolbox is an application about electronics components. it contains detail information about electronics components.
it covers common electronics circuit for a project like
Rectifier diodes BJTs Power BJT MOSFETs Signal diodes TVS etc

Detail information about common electronic circuits

Electronics calculator

you can perform the following calculations with the app
555 Timer astable multivibrator
555 Timer monostable pulse duration
Resistor color code
Series resistors
Parallel resistors
Series capacitors
Parallel capacitors
Voltage divider
LCR impedance
LCR resonance
Operational amplifier (Invertingnon inverting and difference amplifier)
LED resistor value
Zener diode voltage regulator
Inductor winding
CR filter
LR filter
Capacitive reactance
Inductive reactance
BJT parameters
Delta -> star
Star -> Delta
Current divider
Parallel RLC
Series RLC
common circuit calculations
common circuit details
etc

the app contains a section for a explanation of common electronics circuits like
Active rectifier circuit
Band pass filter circuit
Transistor astable multivibrator circuit
MOSFET amplifier circuits
Class A amplifier circuit
Class B amplifier circuit
Differential amplifier circuit
etc