The circuit is a two-stage direct coupled transistor amplifier, which then become self-excited multivibrator. Adjustment potentiometer R1 can change both the duration of the flash, but also can change the flash interval.
Magical lights flashing LM317
LM317 voltage regulator is used as the adjustment element, here to introduce an unusual application, as long as accompanied by few external components, can make a small 12V bulb flashing light.Shown, using component values given, and the signal, when the circuit is connected after the bulbs will flicker frequency 4Hz, of course, if the change in device parameters (R2 or C2, or C2 change when the value of R2, the other the corresponding resistance or capacitor values have changed, so the same with the R2 or C2), the frequency of flashes will become, to the flashing lights stop flashing, the available voltage 1V drive T1.
LM317 itself as transport current 1A, open circuit can automatically limit the current, lamp life is quite long. Interested parties may wish to try.
A multi-purpose flash circuit
Imitation LM3909 SG3909 is an integrated component, can be used interchangeably with the LM3909, the working voltage less than 1.5V, use regular capacitor voltage boost, the 2V pulse sent to the light emitting diodes.
SG3909 pin to schedule such as shown in Figure 7. SG3909 features are:
1, micro-power operation, a large flashlight batteries can work more than one year;
2, the power supply voltage is low, can be from 1V to 5V;
3, drive current, as the oscillator can drive 8Ω speaker;
4, fewer external components, the circuit house from the start, only plus a battery and a capacitor can constitute a flasher;
5, low cost, good brightness.
Figure 1 ~ Figure 6 shows the SG3909 and a variety of light-emitting diode VD H incandescent flash circuit. Flash frequency by adjusting the external resistors, capacitors to adjust.
Component selection: light-emitting diode VD can choose the following: BT104 (yellow), BT304 (green), BT305 (red), other models as long as the LED voltage at 1.5V ~ 2.5V can be used. Switch SA is KNX (1 × 2). H lighting for the 6.3V, 0.1A (screw) or 6.3V, 0.15A (jack). Power GB 4F22-DC6V stacked with battery, DC 6V power supply can also be rectified, this is more economic. Other components is shown in Figure 1 to Figure 6 mark, no special requirements.
High-power battery-powered flashlight
The flash is controlled by a 12V battery-powered cars or boats. It provides 36 ~ 40W output and a variable flash frequency (up to 60 times / min), and off to achieve independence day and night cycle control and photoelectric control, so that the flash power automatically in the night, off during the day. SCR1 and SCR2 composed of a basic DC triggers. Light load received a silicon-controlled rectifier (SCR) of the cathode lead wire to light the other end in ground (negative) potential (which in some cases is needed.) Touch to control time by an ordinary single-junction transistor oscillator circuit (Q1, R1, C3, etc.) to control. Potentiometer R2 and the diode CR1 can be individually controlled on / determined time. Photosensitive resistance junction transistors in a single day and cut off the starting circuit. Flash bulb is 12V, 3A.