Fangrui Product Details Handy, Quick And Easy For Dtl, Ttl And Cmos High Frequescy Response Instant Indication Pulse Memory Function How To Use: 1. Connect Red Clip To + Terminal And Black Clip To - Terminal Of The Power Source Of The Circuit Under Test. The Supply Voltage Should Not Exceed 18v Dc 2. For Ttl And Dtl, Set The Upper Select Switch To The Side Marked Til For Cmos, Set The Upper Select Switch To The Side Marked Cmos, Contact The Probe Pin To The Point To Be Tested. The Leds Will Indicate Its Logic States: A. All Leds Off -high Impedance B. Red Led On - High State (1) C. Green Led On - Low State (0) D. Orange Led On - Pulse 3. For Deteching And Storing Pulse Or Level Ition, Set Lower Select Switch To Side Marked Pulse First. Contact The Probe Pin To The Poin To Be Tested. The Leds Will Indicate Is Basic State. Then Set The Lower Select Switch To Side Marked Mem, The Orange Led Will Light When Any Pulse Or Level Ition Is Detected. The Pulse Direction, In Comparison With The Original Basic, State, Cabe Determined. Af