The DC motor drive circuit composed of L293D is shown in the figure below: L293D is a dual motor control circuit, the left side controls M1, and the right side controls M2. Its ⑧ pin inputs the power '...

The circuit principle is shown in Figure 1. SCR, R1 and AN form a thyristor trigger switch circuit; IC1, R2, VT1, VT2 and BL form a simulated siren circuit.

To solve this problem, I added a relay, a capacitor, two diodes and a resistor to the circuit. In this way, when you sleep at night, turn the fan to the weak position and press the colored light, the '...

Most light-emitting diodes have the function of reverse photodiodes. That is, when a reverse bias is applied to the light-emitting diode, it will generate a small photovoltaic as the light level incre'...

The item left behind reminder alarm introduced in this article is small in size, with an overall size of 17×35×100mm. The device is a system consisting of a transmitter and a receiver, and works in th'...

As shown in the figure is the alcohol detection alarm controller circuit. QM-NJ9 is an alcohol gas sensor. If alcohol smell is detected, the resistance between AB of QM-NJ9 becomes smaller, and the po'...

Power line carrier remote control is particularly suitable for home use because it does not require additional wiring or occupy radio frequencies. Here we introduce a simple and easy-to-make power lin'...

The following circuit is used to drive a 3V powered micro DC motor. This motor has two leads. By changing the polarity of the two leads, the motor can be reversed. The drive circuit is required to be '...

The components of this circuit choose 555 as the main control chip. This is the most classic touch desk lamp circuit. The price is not expensive. The single-pole plate touch is completed through RC di'...

TQ5638 is a receiver that supports KPCS CDMA/GPS working mode. Its electrical characteristics meet the requirements of TIA/EIA 98-C wireless communication standards and can be used in KPCS band-based.'...

As shown in the figure, this is the auxiliary audio power amplifier circuit of LM4732. The audio input signal is added to the in-phase input terminal of LM4732 after passing through potentiometers Rv,'...

TDA2822 is a low-power integrated amplifier, which has the following characteristics: low operating voltage, it can still work normally when it is lower than 1.8V, high integration, few peripheral com'...

As shown in the figure, this is the audio logic level probe circuit. The probe is composed of a voltage comparator, a multivibrator, a piezoelectric ceramic HTD, etc. The latter two form an audio circ'...

This more complete ultrasonic generator is shown in the figure below. It has a timer that can limit the generator to work in a continuous waveform state or in a high voltage pulse state with adjustabl'...

The circuit we introduce here can achieve continuous adjustment from 0.7V-24V, and can achieve an adjustable current limit of 50mA-2A.

The fan M is powered on and runs, cooling the power transformer with air, and the temperature gradually drops. After a period of time, when the temperature drops to the set lower limit temperature con'...

The door open alarm circuit is very simple, consisting of only four components and a 9V battery. The circuit is fixed on the door frame. The reed switch S1 is used as a circuit sensor. As long as ther'...

As shown in the figure, it is the liquid level control circuit of the towerless booster water supply device. The control circuit is composed of a capacitor step-down rectifier circuit, an electric con'...

TDA7294 is a rather innovative DMOS high-power integrated amplifier circuit introduced to mainland China by the famous European company SGS-THOMSON STMicroelectronics in the 1990s.

Here we introduce a new type of transmitter, which is simple to make and has excellent sound quality, and is suitable for high-fidelity wireless audio use.