I once bought a remote control electric curtain. The original control part used infrared remote control, which had a limited range and was inconvenient to use. For this reason, I modified it and repla'...

This article introduces a magnetically controlled door and window burglar alarm with low cost, simple design, stable performance, easy production, simple debugging, easy installation and small size.

The item left behind reminder alarm introduced in this article is small in size, with an overall size of 17×35×100mm, like two matchboxes, and a control distance of 1-5m (adjustable to 15m). It has a '...

A handheld low-voltage electronic self-defense stun gun, composed of a transistor BG to form an oscillator, which stores energy and supplies it to the thyristor automatic discharge circuit to generate'...

The electric energy on the motorcycle is supplied by the magneto on the vehicle. The output voltage of the magneto is stabilized by the silicon rectifier regulator on the vehicle, and then supplied to'...

The pulse frequency multiplier is composed of two gates in the NAND gate CD4011. One of the gates is used to form an inverter to invert the falling edge of the input pulse, so that the circuit is on t'...

The working principle of the application circuit of the device is shown in Figure 5. When showing slides, movies, or videos, the indoor lights are often turned off. When the show is over, the lights m'...

As shown in the figure is an AC voltage multiplication circuit. This circuit is composed of MC1594 four-quadrant multiplier. The circuit is simple and the accuracy is slightly poor. In order to make t'...

The four-way anti-theft alarm circuit is shown in the figure. It is mainly composed of CD40118 integrated circuit chip, which is a multi-way anti-theft alarm circuit and can be used in four-way anti-t'...

TL494 DC motor PWM speed control circuit, the circuit is very simple, the wiring is good and it can work normally without debugging

The circuit is shown in the figure. In the figure, S1 is a click-type reset switch. When S1 is clicked, the battery BT1 quickly charges C1 through R1. When the voltage charged on C1 is higher than the'...

This simple timing socket can time the final stage of trickle current floating charge of the charger. When the trickle current floating charge reaches the set value, the intelligent timing socket auto'...

The universal timer in Figure 1-1 can be set for 5 minutes to 18 hours at a time; the cycle time is from 5 minutes to 20 hours; the total time of timed on and timed off is 18 hours. The control power '...

As shown in the figure, this is a 300kHz signal generator, which is composed of VT1, T1, VD4 and related components to form a voltage-controlled oscillator.

The high-voltage series switching power supply, after designing the experiment, the author obtained the circuit shown in the attached figure, whose output voltage is quite stable and the efficiency is'...

This is a very simple, low cost, hi-fi quality power amplifier. You can implement it in 5 ways, as indicated in the diagram (from 20W to 80W RMS).

Working principle of charging lamp: 220V AC power is stepped down by two non-polar capacitors C1 and C2 in parallel, and then rectified by diodes D1~D4 to obtain pulsating DC voltage (R1 is the discha'...

Circuit Principle: The circuit is shown in the figure below. When the mains voltage is normal (185V-245V), IC1, IC2, IC3, and IC4 all output low level, and relays J1 and J2 do not operate.

The fans used for ventilation and cooling of equipment in factories and mines are usually only manually controlled. This is not convenient enough. Two components (DJ-702 electronic relay and electric '...

This circuit is designed to monitor the charge level of a 12V lead-acid battery. Battery level will be indicated by LED. This simple circuit allows monitoring of the charging process to a higher level'...