As shown in the figure, the repairer has the following functions: it can judge the quality of the diode and the triode online; test the logic level or high-resistance state of the TTL; output the TV horizontal bar signal of 37MHz, 74MHz, 148MHz; output 465KHz, 930KHz, 1395KHz amplitude modulation signal.
In this circuit, 555 and R5, R6 and C8 form an astable multivibrator, and the outputs are respectively added to VT1, VT2 and the like as test signals. When the output is high, VT2 is turned off and VT3 is turned on; when low, VT2 is turned on and VT3 is turned off. Test diodes, triodes, from the LED1, LED2 lighting, you can judge the quality of the tube.
Gps Tracking Battery,Pet Tracker Battery,Gps Car Battery,Toys Lithium Battery
Jiangmen Hongli Energy Co.ltd , https://www.honglienergy.com