Audio logic level probe circuit based on 555 timer

Probe domestic double-head probe 051-BU-5.7L The two heads of the needle are pointed and clawed

The 555 timer is a mid-scale integrated device that combines analog and digital functions. Generally known as 555 made by bipolar process, it is called 7555 in CMOS process. In addition to single timer, there is corresponding double timer 556/7556. 555 timer has wide power supply voltage range, which can be 4.5. Operating at V~16V, the 7555 can operate from 3 to 18V with an output drive current of approximately 200mA, so its output is compatible with TTL, CMOS or analog circuit levels. It has low cost and reliable performance. It only needs several external resistors and capacitors to realize pulse generation and conversion circuits such as multivibrator, monostable trigger and Schmitt trigger.