Transistor oscillator circuit

Transistor oscillator circuit

Simple, low-cost, transistor oscillator circuit, brief analysis, learning oscillator circuit, in the past found that there are several other products that use this circuit to produce a certain frequency of pulse signal. Interesting. To learn.                                                                                                                                                                                                         It can be seen that this circuit is a positive feedback closed loop consisting of two non-gate (inverter) capacitors C1 and C2. The collector output of the Three-Level Tube Q1 is connected to the base set input of Q2, And the collector output of Q2 is connected to the base input of Q1. After the circuit is powered on, the base electrode resistance R2 and R3 provide the base electrode offset current to the Two Transistors Q1 and Q2 at the same time. Enable Two Transistors to zoom in. Although the two three-level tubes have the same symmetric model. However, there will always be slight differences in the circuit parameters, including the two transistors themselves. That is to say, the degree of conduction of T1 and T2 cannot be exactly the same. Suppose Q1 is faster, then the voltage of the D point will decrease faster. This tiny difference will be amplified by Q2 and fed back to the base pole of Q1, and then amplified by Q1 to form a chain reaction, quickly saturated Q1 and ended by Q2, point D is changed to low level "0", and point C is changed to high level "1 ". After Q1 is saturated, it is equivalent to an on-board switch. The capacitor C1 is discharged through it. C2 is charged through it. With the discharge of C1, the base voltage of Q2 increases gradually due to the positive power supply of VCC. When the-point voltage reaches 0.7v, Q2 starts to turn into the amplification area, the chain reaction will immediately appear in the circuit, which is the rapid saturation of Q2. Q1 ends, and the C-point potential substation is "0 ". The D point potential changes to the High Level "1 ". In this case, the capacitor C2 is discharged and C1 is charged. This charge and discharge process will re-saturated Q1, Q2 ended. This cycle forms an oscillation. From above, we can know that by changing the capacity of C1 and C2, we can change the charging and discharging time of the capacitor, thus changing the oscillation frequency. Non-transistor shock Circuit The multi-harmonic oscillator is generally composed of a transistor or integrated block. The multi-harmonic oscillator described in this example uses a thyristor as the main control component, which can directly drive load with relatively large capacity. String 7 For example, the operating principle of a circuit is similar to that of a transistor multi-harmonic oscillator. When the scr1 is powered on, the voltage at both ends of C1 cannot change, so that the-Point potential is close to zero volts, and scr2 does not trigger the voltage and ends. Then, the power is charged by c1 through R1 and scr1, so that the point potential increases gradually. When the UA reaches a certain amplitude, scr2 is triggered through D2. After scr2 is turned on, the voltage at both ends of C1 is added to the anode of scr1 through the control pole of D2 and scr2, And the cathode is added to the anode of scr1, so that scr1 is shut down due to reverse pressure. After that, the capacitor C2 is filled and discharged like C1, so that scr2 ends again, scr2 is turned on again, and the two sets of lights are turned on alternately. Http://hi.baidu.com/e_china/blog/item/0ba3d932197f0b4aad4b5f9d.html