Green laser can create two kinds of laser effects for the customers

The structure of the entire circuit can be seen as added two type II filter network in the shoot-level output on the composition of L1, C1, C2, and L2, C6, C7, respectively. The capacitor C5 is composed of C-type filter network and a time delay network. Slow start to the input voltage V to produce large amounts of high frequency components in the switch and closed the moment the figure of two type Ⅱ network filter out most of the high-frequency component, the DC and low frequency components smoothly after. Reached the resistor R and C consisting of time-delay networks, C2 and C4 in parallel in order to reduce the effect of the inductance of the electrolytic capacitors on the high frequency components. The constant current source circuit design. In order to make the semiconductor laser stability, convection current of the laser is very strict, the power supply circuit must be low noise and stable constant current source driver, the specific circuit shown in Figure 3. For radio frequency wireless presenter  green laser pointer  is more convenient application and operation.
Shown in Figure 3, the constant current source is the op amp U1 and transistors T1, Darlington Q2 current amplification by U2 amplification feedback in order to achieve constant current output. TQ2 adjustment tube high power Darlington transistors, connected as emitter in the form of the semiconductor laser (LD) as the load in series in the launch of the Darlington pole extremely achieved by controlling the Darlington base control of the laser current. The design requirements of the circuit maximum output operating current of 3 A, which requires to promote the Darlington base current is relatively large, but the integrated op-amp generally work in a small current state, can not directly promote the normal work of Darlington, even if we manage to promote their work will result in integrated op-amp itself, power consumption is too large, the temperature is too high, the output of the circuit accuracy, so a small power transistor T1 to promote high-power Darlington.  green laser pointer can meet requirements of the customer used.
Sampling resistor connected to the laser the lower end of the sampling signal amplification and then after a zoom ratio of phase link by U2 then back to the inverting input of U1, constitute the current negative feedback circuit, to achieve the purpose of output constant current. The stability of the laser power control. The optical power feedback using external monitoring of the output photocurrent of the photodiode, amplifier and then by the A / D conversion evacuation CPU processing, come to control the amount, adjust the laser current, and thus the closed-loop control of laser power. Temperature control in this system using a semiconductor refrigeration, which is a thermoelectric cooler, control flow magnitude and direction of the thermostat current, can the laser cooling or heating, to control the operating temperature of the laser.  green laser pointer  is to meet different requirements of the customer in different locations for different purposes.
Although the slow-start circuit to eliminate the hazards of high-frequency impulse current, but can not effectively prevent DC or low frequency current overload hazards of semiconductor lasers, therefore, should be established to the overload protection circuit. General can be used to limit the current protection circuit. If you work long hours in the case of short circuit, overheating will still lead to adjustment of tube damage can take the closure of the protection circuit. The accuracy depends mainly on the over-voltage protection zener diodes, and its operating point drift is very small with flowing through the regulator current and ambient temperature changes, therefore, the design must be selected in stabilizing the voltage regulator. The system software uses a modular design, top-down, gradually refined using subroutine constitute each module, such as the initialization module, keyboard module, display module. Main program flow chart shown in Figure 4.   green laser  can create two kinds of laser effects for the customers.