Simple FET Two Lamp Flasher Circuit

Two Field Effect Transistors (FETs) configured similarly to a simple astable multivibrator are used to make the simple two alternate lamp flasher circuit.

What is a FET Lamp Flasher Circuit:

This electrical circuit which is based on FETs is commonly used to flash lights and bulbs.

Along with a few other circuits components it makes use of a few field effect transistors.

Circuit Working:

Parts List:

These FETs conduct cyclically switching two bulbs from ON to OFF.

The circuit diagrams R/C values are used to define the flashing rate which is set at around 1/3 Hz.

Almost any desired flashing rate can be achieved by simply adjusting the values of the resistor or capacitor showing the circuits adaptability.

This flexibility makes it easier to modify to meet certain application needs or preferences.

Connecting many MOSFETs in parallel removes the requirement for any specific current dependent components and allows for higher rated bulbs.

The circuit is capable of controlling higher load needs because of its adaptability.

Standard 12V to 14V lights with a cold filament and a 6 ohm resistor are easily used in this design.

The circuit uses 2 amps of current at start when powered by 12 volts.

With a lower current of just 200mA the circuit functions effectively once the light switches between its ON and OFF states while in use.

Formula:

An astable multivibrators frequency (f) is roughly calculated in a very simple manner:

f = 1 / (1.4 * R * C)

where,

• f is the approximate frequency in hertz Hz
• R is the equivalent resistance expressed in ohms Ω
• C is the capacitance in farads F which can be either C1 or C2 depending on the design.

Crucial Information:

This calculation may only provide a rough estimate for certain FET flasher circuits especially those with complicated designs.

Factors such as transistor characteristics, component tolerances and leakage currents might change the actual frequency.

How to Build:

Build a Simple FET Two Lamp Flasher Circuit using the below mentioned steps for connections:

Gather Components:

• Gather the required circuit parts such as lights, a power supply, resistors, capacitors and FETs.

Place FETs:

• Make sure the two FETs are positioned correctly by placing them on the breadboard.

Connect Resistors and Capacitors:

• As shown in the circuit diagram above one needs to connect the resistors and capacitors using the values that indicate the flashing rate.

Adjust Flashing Rate:

• Try changing the resistor or capacitor values to get the flashing rate one needs.

Connect Lamps:

• Ones the lamp is connected make sure it meet the circuit requirements for 12V to 14V lamps with a 6 ohm resistance.

Power Supply Connection:

• Connect the breadboards power supply to the proper connections.

Observe Starting Current:

• Keep in mind that the circuit draws 2 amps of electricity when powered by 12V.

Conclusion:

An electronic fan may effectively build a basic FET light flasher circuit and modify its workings to suit its own requirements.

Make sure the circuit is dependable and functional and at times verify the values of the connections and components.

References:

Datasheet MOSFETIRF540