The circuit in Figure 1 uses LEDs rather than 4 lamps and is powered from a DC power supply or cells. The circuit uses a IC-555 (timer) configured as an astable multivibrator driving a power transistor.
The frequency is controlled by P1 in a range determined by C1, and the pulse duration is determined by R2. These components can be changed from 4.7 to 47 k. White bright LEDs are recommended, but depending on the application, you can use common LEDs of any color.
The power drain depends on the number of LEDs used in the project and also on the values of R4 and R5. These resistors can be increased if you don’t need high power or if you want to use common LEDs.
IC-1: 555 integrated circuit and timer
Q1: TIP32 PNP silicon power transistor
LED1 to LED4: White LEDs (see text)
P1: 1 NE) lin or log potentiometer
R1, R2: -10 k ohm x 1/8 W resistors, brown, black, orange
R3: 1 k ohm x 1/8 W resistor, brown, black, red
R4, R5: 47 x 1/8 W resistors, yellow, violet, black
C1: 1 µF polyester or electrolytic capacitor
S1: On/off switch (SPST)
B1: A 6 V or four AA, C, or D cells with holder
Other parts: PCB or solderless board, knob for P1, wires, solder, plastic box, etc.
