Logic Tester HYT-07

From the shop's description

Feature: Tests all logic families. TTL,LS,C-MOS,ETS Available 25nSec, 20MHZ Audio & Visual Specification: Working Voltage : DC4-16V Current Consumption : Max. 32mA at 5V Frequency Response : Max. 20MHz Response `Pulse Width : Longer than 25nsec Input Impedance : Min. 1M ohm Input Overload Protection : ± 250V DC/AC Supply Voltage Protection : ± 50V DC/AC Operating Temperature : -20-+70°C Troubleshoot using Logic probe: The logic probe or digital tester is normally a low cost hand-held probe contained within a pen-like tube with indicator lights to show the state of the line being probed. The logic probe has a pointy metal tip that is touched to the specific point you want to test. Logic probe connections: There are three connections to the logic probe: Black lead with crocodile clip: There are two leads which generally come out of the opposite end of the instrument to the metal probe itself. The black lead is connected to negative ground and is also used as the return. Red lead with crocodile clip: This lead will have red on it somewhere, possibly just on the crocodile / alligator clip and is used to connect to the supply. Be careful to connect this to the logic supply which will normally be +5 volts. Probe tip: The probe tip is a metal point used for probing the circuit.