Simple 12V Single Lamp Flasher Circuit make lamp blink ON and OFF which looks cool.
This circuit is simple and strong and is good for 12V car lamps.
It is used in to turn signals, warning lights and fun lights.
This one use BC557 transistor and IRF530 MOSFET.
It works by charge and discharge capacitor to control blink time.
Circuit Working:
Parts List:
| Component Type | Specification | Quantity |
|---|---|---|
| Resistors | 6.8k 1/4 watt | 1 |
| 220k 1/4 watt | 1 | |
| 22k 1/4 watt | 1 | |
| Capacitor | Electrolytic 100μF, 25V | 1 |
| Semiconductors | MOSFET IRF530 | 1 |
| Transistor BC557 | 1 | |
| Diode 1N4002 | 1 | |
| Switch SPST | 1 | |
| 12V incandescent lamp | 1 | |
| Battery 12V | 1 |
When circuit turns ON capacitor C1 start charging through resistor R2.
Voltage on C1 goes up and then turns ON the transistor Q1.
Q1 ON and C1 discharge through resistor R1.
This pull down gate of transistor Q2.
Q2 turns ON and act like switch, lamp L1 lights up.
C1 keep discharging and gate voltage of Q2 goes down and Q2 turns OFF.
Lamp goes OFF and process repeat.
Flash speed depend on how fast C1 charges and discharges and this is set by R2 and C1.
Circuit can get power direct from car battery.
Formulas with calculations:
Formula and calculation for simple 12V lamp flasher:
Time for capacitor to charge:
T = R × C
R = 220k, C = 10μF = 0.00001F
T = 220,000 × 0.00001 = 2.2 sec (approx)
Full flash cycle time:
T = 0.693 × R × C
T = 0.693 × 220,000 × 0.00001 = 15.246 sec (approx)
Flash speed (frequency):
f = 1 ÷ T
f = 1 ÷ 15.246 = 0.066 Hz
Flash speed is around 4 flashes per minute.
How to Build:
To build a Simple 12V Single Lamp Flasher Circuit follow the below steps:
- Gather all parts shown in diagram.
- Connect Q1 collector to one side of R1 and other side of R1 to GND.
- Connect Q1 base to negative of C2 and positive of C2 to one side of R3 and other side of R3 to Q2 drain.
- Connect Q1 emitter to +12V.
- Connect C1 positive to point between Q1 emitter and D1 and negative of C1 to GND.
- Connect one end of R2 between Q1 base and C2 negative and other end of R2 to GND.
- Connect Q2 gate to point between Q1 collector and R1.
- Connect Q2 drain to one side of R3.
- Connect Q2 source to GND.
- Connect lamp L1 and switch S1 between +12V battery and GND.
Conclusion:
This Simple 12V Single Lamp Flasher Circuit is easy, cheap and useful.
It shows how transistor and MOSFET make flashing.
Change resistor and capacitor to adjust flash speed.
It is good for car lights, alarms, fun lights and is great to learn timing circuit.
References:
Recreate an inline 12 Volt Electronic Flasher unit for LED turn signals