Practical flashing light circuit

Flasher/Light Control This circuit is a two-stage direct-coupled transistor amplifier connected as a self-exciting multivibrator. Adjusting the potentiometer R1 can change both the flash time and the flash interval. The wonderful use of LM317 flashing light LM317 is often used as an adjustment component in voltage regulators. Here I will introduce to you an unusual application. As long as it is equipped with a few external components, it can make a small 12V light bulb flicker. As shown in the figure, using the given component parameter values ​​and signals, when the circuit is connected, the small light bulb will flash at a frequency of 4Hz. Of course, if the component parameters (R2 or C2) are changed, when R2 or C2 changes value, other corresponding resistors will Or the capacitance value is also changed to make it the same as R2 or C2), the flashing frequency will also change. To make the flashing light stop flashing, T1 can be driven with a voltage of >1V. Since the LM317 itself transmits current >1A, the circuit can automatically limit the turn-on current, so the life of the bulb is quite long. Those who are interested may wish to try it. A multi-purpose flash circuit SG3909 is an integrated component imitating LM3909. It can be used interchangeably with LM3909. The operating voltage can be lower than 1.5V. It uses a timing capacitor to increase the voltage and send 2V pulses to the light-emitting diode. The pin arrangement of SG3909 is shown in Figure 7. The characteristics of SG3909 are: 1. Micro-power operation, one large flashlight battery can work for more than one year; 2. Low power supply voltage, ranging from 1V to 5V; 3. Large driving current, as an oscillator, it can directly drive 8Ω speakers ; 4. Few external components, self-starting inside the circuit, only one battery and one capacitor are needed to form a flasher; 5. Low cost, good brightness. Figures 1 to 6 show various light-emitting diodes VD and incandescent lamp H flasher circuits of SG3909. The flash frequency can be adjusted by adjusting external resistors and capacitors. Component selection: The following types of light-emitting diodes VD can be used: BT104 (yellow), BT304 (green), BT305 (red). Other light-emitting tube models can be used as long as the working voltage is between 1.5V and 2.5V. Switch SA is KNX (1×2). The lighting H is 6.3V, 0.1A (screw) or 6.3V, 0.15A (socket). The power supply GB uses a 4F22-DC6V laminated battery, or a rectified DC 6V power supply, which is more economical. Other component parameters are marked in Figures 1 to 6, and there are no special requirements. . . . . . . . . . . . . . . . Battery Powered High Power Flasher This flasher is powered by a 12V car or motorboat battery. It provides 36~40W output and variable flash frequency (up to 60 times/min), and can realize independent on-off cycle control and photoelectric day and night control, allowing the flasher to automatically power on at night and power off during the day. SCR1 and SCR2 form a basic DC flip-flop. The lamp load is connected to the cathode lead of a silicon controlled rectifier (SCR) so that the other end of the lamp can be at ground (negative) potential (this is required in some applications). Trigger timing is controlled by a common one-junction transistor oscillator circuit (Q1, R1, C3, etc.). Potentiometer R2 and diode CR1 can independently control the on/off timing. The photoresistor cuts off the unijunction transistor starting circuit during the day. The flash bulb is 12V, 3A.