Very easy and simple LED flasher with only three components: a flasher IC, a LED and a electrolytic capacitor.

Component list:

LED1_________Red LED
C1___________100uf/16V
IC1__________LM3909
Battery______1.5V AAA

This is the circuit of LED color fade effect. Just like the name of the circuit, the light intensity of LEDs in this circuit will fade from high  intensity to low intensity and then off.

Here the final result preview:

This is running LEDs circuit which use timer ID NE555N and logic IC 4017N. IC 555 act as a multivibrator and generate frequency to be used for 4017 clock input. R2 is a linear potensiometer to adjust clock frequency and of course the frequency of the blinking LEDs as well.

This is the circuit of dancing LEDs which consists of 10 units LEDs. The circuit works like a audio level meter. The LEDs will be dance sequence with the sound level that entering the microphone.

Components list:
R1_____________10K 1/4W Resistor
R2,R3__________47K 1/4W Resistors
R4______________1K 1/4W Resistor
R5,R6,R7______100K 1/4W Resistors
R8____________820R 1/4W Resistor

C1,C3_________100nF 63V Ceramic or Polyester Capacitors
C2_____________10΅F 50V Electrolytic Capacitor
C4____________330nF 63V Polyester Capacitor (See Notes)
C5____________100΅F 25V Electrolytic Capacitor

D1___________1N4148 75V 150mA Diode
D2-D11_________5 or 3mm. LEDs (any type and color)

IC1___________LM358 Low Power Dual Op-amp
IC2____________4017 Decade counter with 10 decoded outputs IC

M1_____________Miniature electret microphone
SW1____________SPST miniature Slider Switch
B1_______________9V PP3 Battery
Clip for PP3 Battery

Here the analog flip-flop which built based on 2 transistors work as switch. This is very easy made and very cheap circuit. You can use this circuit as “the first project” for your students…

and the result should be like this: