This article describes a direct AM radio that is loaded with YS764 integrated circuits and a small amount of components. YS764 can be applied to the production of card radios, lighter radios, etc., with very good economic value. The outer shape of the YS764 integrated circuit is like a 9014 small power triode, and the three pins are 2 feet (inputs), 3 feet (outputs), and 1 foot (common place). The Schedule is the main parameters of the YS764 integrated circuit.
Circuit work principle
Figure 1 is a circuit principle block diagram of the YS764 radio. The radio uses a magnetic antenna TA as a receiving antenna. It can receive the electromagnetic wave signal of space propagation and convert it into a high frequency signal to receive. The input tuning loop consists of coil L1 and variable capacitance C1. Tuning loop can select the signal of a certain station required in many carrier signals, and play a role in selecting a station. The high-frequency amplifier multi-stage enlarges the received weak signal and then sent to the detector. Because the received high frequency amplitude signal has a frequency of several hundred kHz to tens of MHz. Such a high alternating current cannot make a sound of the headset or speaker, so it is necessary to take the audio signal in the high frequency signal by the detector. Then, then the audio amplifier consisting of a triode, the detected audio signal is fully enlarged, and finally convert the electrical signal into a sound signal by the headset (speaker).
Typical application circuit
The headset radio YS764 can directly promote a high-sensitive headset. The equivalent impedance (RL) of the earphone should generally be 100 to 1500 Ω (appropriately connected to RX to meet the requirements). Figure 2 is a working line for a high sensitive headset (plug). A single tube amplifier is added in Figure 2, a low-cost crystal headset can be used (see Figure 3). This is a work line of a forefront of a forefront of a foreign (or ear mounted) micro radio. Figure 2, in Figure 3, L1, C1 constitute a tuning loop. The coil L1 can select a wire diameter 0.1 to 0.3 mm enameled wire, from 80 to 130 turns on a magnetic rod such as 5 × 23 (mm) or 50 × 12 × 4 (mm). The tuning capacitor C1 can purchase a miniature variable capacitor that is small than the size of the fine-tuning capacitor, and can also be used in small seals. The battery uses a GB button battery or No. 6 battery. Other components parameters see Figure.
Ultra-equilation radio Figure 4 is a line diagram of an over-extra differential radio. The YS764 integrated circuit is used as an intermediate frequency amplifier of the radio, which can make the circuit structure simple and compact. The other parts of the circuit are the same as the ordinary ultra-unhevariated radio. Readers should pay attention to the following issues when using the YS764 integrated circuit design to do printed circuit boards: 1 Output decoupling capacitor should be as close to the output and ground points. 2 All contacts are relanging short, and close to the YS764.3 tuning capacitor C1 to maintain a distance from the battery and headphones (speakers). 4 Tuning capacitor C1 The movable lead wire should be welded to the connection point of the automatic gain control resistor R1 and the bypass capacitor C2. The above measures are mainly to prevent parasitic coupling, reduce noise interference and human sensing. The YS764 integrated circuit has a wide operating frequency range, high power gain, can be applied to multi-faceted circuit design.
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