This is a practical household electronic gadget. When someone comes to visit (standing in front of the door), it can inform the owner that there is a guest outside the door. It is equivalent to an act'...

The light-controlled electronic bird introduced in this article is an interesting electronic toy. It uses the changes in the intensity of the light shining on it to emit bird calls with varying pitche'...

The ordinary doorbells used at home have a single function and do not have the functions of monitoring and listening. The following introduces a visual (audio) doorbell that combines an ordinary doorb'...

This device is actually an extremely sensitive static electricity detector that can issue early sound and light warnings based on discharges inside the cloud before a lightning strike occurs. The ante'...

The schematic diagram is shown in Figure 1. The delay switch introduced after 1 and 2 is an equivalent switch that controls the on and off of the exhaust fan. The main circuit consists of a bridge rec'...

Knowledge about overvoltage protection circuits, an example of an overvoltage protection self-locking control circuit, introduces the circuit composition of the overvoltage protection circuit, the wor'...

As shown in the figure, the inverting gain circuit composed of MAX4100/4101, the amplifier gain is determined by the ratio of RF to RG, and will not affect the frequency compensation of the amplifier.'...

The principle is shown in the figure below. This circuit uses 12AX7 for two-stage amplification, followed by 12AU7 cathode follower as signal buffer. As we all know, Marantz 7-tube preamplifier is fam'...

As shown in the figure, LM1876 is used to assist the audio power amplifier circuit. The audio input signal is added to the input terminal 8 pin of LM1876 after passing through the potentiometers RV, C'...

The attached figure is a sensor interface circuit using a differential amplifier. In this example, since the sensitivity needs to be increased from 30mV/A to 400mV/A, the gain of the amplifier should '...

The figure shows the flashlight module circuit. When the battery pack consisting of four nickel-cadmium batteries is fully charged (J1 has no voltage), a 4.8-volt DC current flows through the trimmer '...

The circuit in Figure 1 is a 60Hz digital clock time base circuit consisting of a 12-bit binary serial counter/frequency divider CD4040 and a six-phase inverter CD4069.

The author made an AC LED energy-saving delayed switch lamp using a TV antenna amplifier power box with a socket, an H-shaped energy-saving lamp circuit board, six components and 16 Φ3mm white high-br'...

The digital strain gauge circuit composed of MAX1492/MAX1494 is shown in the figure below. The bridge voltage is provided by the internal reference voltage of MAX1492/14. The differential analog input'...

The system is maintained by a series of Arduino controllers. Watering cycles, pH levels, nutrient levels, lighting cycles, and ventilation fans are all maintained via the Arduino.

The input and output voltage inversion circuit of X660 is shown in the figure. The input voltage is 1.5~5.5 V, and the output voltage can be -1.5~-5.5 V after voltage inversion.

Figure (a) shows a 50W output power amplifier circuit composed of a STK084G thick film amplifier. STK084G is a thick film integrated chip with a distortion rate of 0.01% at 20kHz and 50W. Its internal'...

The 12V battery automatic charging circuit will automatically monitor the battery voltage. When the battery voltage is lower than 11V, the circuit will automatically charge the battery until the batte'...

The attached figure is a Class D amplifier without Lc low-pass filter. MAX9708 is a Class D amplifier integrated circuit produced by Maxim Corporation.

This water level alarm can sound an alarm in time when the water level in the water tank is full. The square wave signal generated by the transistor oscillator in the circuit is sent into the water th'...