This simple kit is ideal for beginners to construct. It is easy to assemble.

The kit "sings" like a bird continuously when you press the button switch. Can be used a novel door chime.

This kit creates a visual effect of two lighted "balls" spinning in a rectangular path.

Running speed adjustable via a trim pot (preset).

This kit creates a visual effect of two lighted "balls" spinning in a rectangular path.

Running speed adjustable via a trim pot (preset).

This kit flashes two LEDs alternately. Built around two transistors and a couple of parts.

Ideal for beginners to learn soldering skill.

This is the electronic version of conventional dice with one to six dots on its faces.

Press and release the button and the 7 LEDs will display the outcome.

A special IC is used to generates 5 ~ 12 melodies.

Two buttons are provided to start the music. One for starting a new song. The other for repeating the same song.

A special IC is used to generate a simple melody.

The kit will play the melody continuously as long as power remains connected.

This adaptor uses a voltage regulator IC to provide stable 9V or 12V current (@200mA).

Replaces 9V batteries and saves you cash. A must if you are an active kit builder.

* Power Transformer included

Detects rain/ water and warns you with a loud beeping sound.

Can be modified to detect water level in a water tank or container.

* Speaker included

A very useful battery-power mini audio power amplifier. Very wide supply voltage range.

* Speaker NOT included

This module counts up from 000 to 999.

However, modules can be joined to count greater digits.

* Counts up only

Pressing a button, a "ball" will spin around 10 LEDs. When the button is released, they will slow down and stop a one number.

Auto cut-off after a few seconds.

A low power transmitter that sends your voice to a remote FM radio.

Frequency is adjustable and falls within FM broadcast band (88 ~ 108MHz).

Can be modified to transmit CD player or TV sound.

The kit produces a "clicking" sound that resembles a mechanical metronome.

An LED flashes in synchronization with each beat.

Adjustable rate

This kit consists of two independent BTL IC power amps.

Ideal for multi-media applications due to its small size and low supply voltage.

Simple yet effective wired intercom with good sound quality.

Comes with "CALL" buttons on both sides.

* Low power consumption

The kit amplifies telephone conversation (of both parties) over a miniature speaker. Direct connection to phone lines that eliminates power lines hum.

Clear sound due to the use of active low-pass filter.

Red LED to indicate logic HIGH while a green one indicates LOW.

Both off for open or floating.

Pressing a button, two LEDs will flash rapidly.

Release the button only one LED remains on. (which represents either a "head" or "tail").

High quality sound power amp that uses a hybrid IC. Use of IC simplifies the design.

With On-board rectifiers and filter cap. Just add transformer.

* Transformer NOT included, IC used: STK-401-040

Uses J-FET input Op-Amp for low noise.

On-board rectifiers, filter cap and voltage regulator (with Tone On/Off and loudness switches).

* Transformer NOT included

Provides stabilized DC voltage with current up to 1.5A. Current limit of 0.6A and 1.5A is selectable via a slide switch.

* Transformer NOT included * Heat sink included but not shown here

This running lights kit has 10 LEDs arranged in one row. A "ball" swinging back and forth on the row.

This kit uses Pulse-width-modulation or PWM to control load power (brightness of light bulb or speed of motor).

PWM does not waste energy as heat and therefore has better efficiency.

* Power MOSFET included

A classical design of audio power amp using a standard circuit and a common op-amp IC plus many transistors.

The kit has a on-board speaker protector with power-on delay. Good sound quality.

* Heat sink included but not shown

An ideal starter kit for beginners.

May seem too simple for experiences hobbyists. Circuit consists of a transistor-transistor astable multi-vibrator.

Used by hanging it on a metal doorknob.

When a visitor or burglar touches the knob, the kit produces a loud beeping sound.

Displays the output of power amp by driving 10 pieces of LEDs in either a dotorbar graph fashion.

Protects your speakers from damage in case the power amp breaks down.

Provides a few seconds of delay on power-up, eliminating the turn-on "POP".