How to make electric motorized tachometer tachometer circuit diagram analysis
The professional tachometer circuit is complicated and expensive, and the general fans are limited by economic conditions and cannot afford to purchase. The author designed a simple electric tachometer that can be used for speed testing of general objects. The speedometer circuit is shown in Figure 1. The circuit is very simple. Only a single-tube amplifying circuit of a triode is used. When the speed measuring motor M is driven, a weak current is generated. After the current is amplified by the transistor Q, the micro-ampere is pushed. The head A indicates that the faster the speed of the measured object, the larger the current generated by the speed measuring motor, and the larger the reading of the meter head, and W is used to adjust the size of the indicator value of the meter. When making, select the components as shown in Figure 1, where M is a miniature toy DC motor; A selects a 100uA meter head, preferably the pointer is in the middle of the dial, so that when the speed is measured, it is not subject to the direction of rotation of the object to be measured. Restriction, otherwise the test direction will be wrong, the hands will be reversed and the head will be damaged; W can be used with a linear potentiometer with a power switch, so that it is easy to draw a uniform test gear scale line on the panel; the power supply can choose 9V laminated battery . The circuit is simple and does not need to make a printed circuit board. It can be lap welding. After soldering, the whole device is placed in a suitable small box. The appearance is shown in Figure 2. The speedometer uses a flexible rubber connector, such as the pressure roller of the recorder, that fits over the motor shaft. After the production is completed, the calibration is performed with a standard tachometer, and the scale of each test range is marked on the panel, as shown in Fig. 3. When using, press the speed measuring head on the measured object and adjust the W button so that the pointer can be estimated at the 2/3 scale of the meter range and the value of the test file marked with the W button. For example, to test the speed of the motor, just press the speed measuring head on the shaft of the motor shaft. This speedometer can also be used to test wind speed, liquid flow rate and other items with appropriate speed measuring heads. Fans can use their imagination and design by themselves. FUME EXTRA 1500PUFFS Shenzhen Xcool Vapor Technology Co.,Ltd , http://www.xcoolvapor.com