1, ASK refers to the amplitude keying mode. This modulation method modulated the amplitude of the signal according to the difference of the signal. Here the LM358 has pin 123 and a peripheral subcalled post-comparator (in-phase hysteresis voltage comparator)), the LM358's 567 pin and peripheral subweighed preamplifier.
2, solution: the triangle connection composed of nodes 2 and 4 is equivalent to the Y-type connection in the right figure. R1= (3×5)/(3 2 5) = 5ω, R2= (3×2)/(3 2 5) =0.6Ω, R4= (2×5)/(3 2 5) =1Ω. Rob= (0.6 4) ∥ (1 1) =1 (Ω). Rab=Rao Rob=5, 1=5Ω. R is equal to 5, 5 is equal to 4Ω.
3. The basic problem of my teaching circuit analysis is shown in the figureAs shown, when t=0, the switch S is closed, and the circuit is in steady state before the switch is closed. Find Uc at t0. ... As shown in the figure, when t=0, the switch S is closed, and the circuit is in steady state before the switch is closed. Find Uc at t0.
4, first analyze the circuit is in series or in parallel, the ammeter as a wire, the voltmeter as a break, can wipe, simplify the circuit. Then according to the specific analysis of the question. The identification and judgment of the circuit include the judgment of the correct circuit and the wrong circuit, the judgment of the series circuit and the parallel circuit. The fault circuit includes missing necessary components in the circuit (necessary components are power supply, electricity consumption)The road principle. This circuit is a classic 315MHz wireless transmitter module circuit. '>315M transmitting circuit principle. This circuit is a classic 315MHz wireless transmitter module circuit.
At static, 12V provides voltage to the C pole of Q2 through the B-E of LRQ1. When DATA comes to data, Q2 is switched on. At this time, the E pole of Q1 is at 0 potential, and Q1 is cutoff at the original static. When the E pole of Q1 has a potential of 0, the Q1 tube is switched on so that the C pole signal is the crystal frequency of the B pole.
The principle is that when the IN terminal inputs a signal (supposeAt this time is positive) so that the transistor into the working state of the moment due to the existence of L1, its collector will appear on an anti-belief signal, the signal is C1 and C2 partial pressure added to the emitter, reducing the emitter potential, that is, to expand the Vbe, obviously a positive feedback, coupled with the resonance of LC1 and C2: It should be close to the crystal's natural frequency of 315MHZ, so it oscillates.
M Wireless module SR9915 is a module specially designed for superheterodyne reception, its compact size is only 35x13x8 mm.
Communication method:AM Operating frequency: 315MHz and 433MHz Frequency stability: ±200kHz Receiving sensitivity: -106dBm Static current: ≤5mA Operating current: also ≤5mA Operating voltage: DC 5V Output mode: TTL level The characteristics of the receiving module are: The operating voltage is 5V, the static current is as low as 4mA, and as a super-regenerative receiving circuit, its sensitivity reaches -105dBm.
encoding is relatively simple, that is, decoding a little trouble, if the distance is very close, it doesn't matter, the distance is far from a good encoding and decoding method. You'd better read it firstHow about the receiving module? There is something wrong with my receiving module, which can detect the signal even when there is no signal. I don't know if the signal's high or low. I don't know. It looks low. If the voltage is not vcc or GND, there is a problem with the module.
M wireless transceiver module scheme development is generally based on the relevant transceiver chip, MCU control architecture to achieve the relevant functions.
2, the above is the schematic diagram, the principle is the principle of electromagnetic induction.
3, the so-called wireless charging technology only uses the electromagnetic wave induction principle, and the related AC induction technology, at the sending and receiving end with the corresponding coil to send and receive inductive AC signals to charge. Nothing high-tech, just magnetic fields! There's a coil on the charger, and there's a coil on the battery. It's closeIt forms something like a transformer. But it's very inefficient, and it's very radioactive.
4, wireless charging technology is the use of electromagnetic induction principle, in the sending and receiving end with the corresponding coil to send and receive inductive current to charge.
5, principle: the DC-DC switching power supply is divided into two parts at the high-frequency transformer, using resonant coupling; Then use RFID technology for data communication and current feedback. In a single-phase bridge rectifier circuit, if a filter capacitor is connected, the output voltage (that is, the voltage at both ends of the capacitor) is an AC input when the load is openThe peak voltage, that is: U output =414*U input, that is, root 2 times the input voltage.
6, mobile phone wireless charging is a relatively novel charging method, the principle is actually very simple, is to separate the ordinary transformer primary and secondary levels to achieve the purpose of wireless. Of course, the working level of wireless charging is relatively high, and even the role of energy transfer can be achieved between the iron core and the direct coil can be abandoned. Drawings to there are a lot, but will not send pictures, to tell you about the simplest wireless charging.