- Build Your Dynamic LED Rhythm Circuit
- Dark Activated LED Flasher: Bowes Circuit Design
- Build a Stunning Two LED Flashing Circuit with Potentiometers
- Electronic Dice: Build Your Own Random Number Generator!
- Build a Rotating Back Light: 555 Timer Circuit Diagram
- Flashing Lamps Circuit: 230V AC with SCR Timing
- Portable 230V AC Lamp Flasher Circuit Diagram
- Build Your 4017 Decade Counter – A Brilliant 9-Step Sequence
- Build Your Own Flashing Lamp Circuit – 10W LED Support
- Pulsating LED Circuit: Build Your 4s Cycle Effect
- High-Intensity LED Flasher Circuit Diagram – Build Your Own!
- Build a Reactive LED Circuit: Diagram & Parts List
- Pulse LED Circuit: Build a Dynamic Two-Strip Design
- 12 Stage Neon Sequencer: Circuit Diagram & Build Guide
- Flash Lamp Circuit: Build Your Own Flasher
Build Stunning Pulsing LED Strips with This Circuit!
Two sets of LEDs exhibiting a reciprocal fading effect
9V Battery-powered portable unit
Circuit diagram
Components:
- R1, R2 2.2K 1/4W Resistors
- R3 22K 1/4W Resistor
- R4 1M 1/4W Resistor (See Annotations)
- R5 2M2 1/4W Variable Resistor (See Annotations)
- R6, R10, R11, R14, R15 10K 1/4W Resistors
- R7, R8 47K 1/4W Variable Resistors (See Annotations)
- R9, R13 27K 1/4W Resistors
- R12, R16 56R 1/4W Resistors
- C1 1µF 63V Polyester Capacitor
- C2 100µF 25V Electrolytic Capacitor
- D1-D4 various 5 or 3mm. LEDs (any type and color) (See Annotations)
- IC1 LM358 Low Power Dual Operational Amplifier
- Q1,Q2,Q4 2N3904 45V 800mA PNP Transistors
- Q3,Q5,Q6 2N3904 45V 800mA NPN Transistors
- SW1 SPST miniature Slider Switch
- B1 9V PP3 Battery
- Clip for PP3 Battery
Device purpose:
This circuit activates two LED strips in a pulsing manner, specifically one LED strip transitions from an extinguished state, gradually increasing its illumination, subsequently decreasing its brightness, and so on, while the other LED strip performs the inverse operation. Each strip can be constructed from two to five LEDs when utilizing a 9V power supply.
Circuit operation:
The dual Operational Amplifiers contained within IC1 are responsible for generating a triangular waveform. The rising and falling voltages obtained at pin #7 of IC1 drive two independent circuits formed by a 10mA constant current source (Q1, Q2, and Q5, Q6) and a driver transistor (Q3 and Q6). R4, R5 & C1 represent the timing components; altering their values allows for adjustable modification of the complete period. R7 & R8 adjust the brightness of the LEDs.
Annotations:
- For those desiring to eliminate the use of variable resistors, suggested values for a 9V supply are: R4=3M9, R9 & R13=47K, and trimmers replaced by a short circuit.
- When intending to employ a wall-plug transformer as a power supply instead of a 9V battery, a supply voltage of 12V can be utilized, permitting the utilization of up to 6 LEDs per strip, or a supply voltage of 15V, allowing for the use of up to 7 LEDs per strip.
- In such cases, the values of the trimmers R7 & R8 should be modified to 100K.
circuit from http://www.redcircuits.com/