Logic probe
O.K. Machine and Tool has introduced model PRB-1 digital-logic probe that simplifies troubleshooting of digital circuits. The small self contained probe requires no adjustments, although it replaces a large, expensive and cumbersome scope for many types of digital servicing.
No switching is needed when changing from one logic family to another. The high LED lights when the probe input exceeds 60 % of the supply voltage. When the input is lower than 15 % of the supply voltage, the low LED lights. Neither LED lights when there is no input voltage. Pulses of shorter than 10nS can be detected up to 50MHz repetition rate. Short pulses are lengthened in duration to 50mS by a pulse stretcher.
The probe has power-polarity protection and overvoltage protection to 70Vdc. Input impedance of 120K ohm does not load the digital circuit. Standby current with neither LED lighted is only 15µA, while both LEDs increase the drain to 9.5mA (taken from the digital circuit).
Operating conveniences include a pocket clip, capped and replaceable probe point, and a truth-table printed on the probe body.
Volt-Ohm-Milli-ammeters
Simpson Electric has announced a new 260 series of VOMs. The units have four new features: recessed, insulated panel connectors with matching reverse-type elbow safety test leads; a double-fused protection network located in the battery-and-fuse compartment; and an off/transit position on the function switch that protects the meter movement during transit. This position shunts the meter movement and opens the internal connections to the common and + jacks.
The basic 260-7 is priced at $103. Options include mirror scale, additional relay overload protection and roll-top case. Probes and protective cases are included.
Dual-trace 25MHz portable scope Gould has developed the OS1200, a lightweight 25MHz dual-trace scope. The unit features a 5-inch rectangular CRT with internal graticule. The unit's 14ns risetime, 6kV accelerating potential, and signal delay make the instrument useful for digital work involving narrow pulses with fast rise-times and low repetition frequencies. Basic time-base speeds range from 200ns/cm to is/cm with vernier control over a range of 2.5:1. The dual input channels have maximum sensitivity of 2mV/cm over the full 25MHz bandwidth.
The price for the Gould OS1200 with probes is $1299.
Compact video generator
New from Hickok Electrical Instruments is the model 240 video generator. It features both a video and adjustable-RF output, 10-step gray-scale staircase, 3- and 10-bar gated rainbows, a trigger output for use with scopes and a built-in battery check position. The 10-step gray-scale staircase simplifies detection of video compression. The three-bar gated rainbow permits fast chroma checks and is useful for vectorscope measurements.
The 240 operates from an ac adaptor (included with unit) or two 9V batteries. Two output leads, provided with the unit, are stored in its snap-on protective thermoplastic cover.
The 240 video generator sells for $159.
Auto-ranging capacitance meter A portable autoranging 3 1/2-digit digital capacitance meter is now available from B&K-Precision. Model 830 automatically selects the correct range of 10 ranges when an unknown capacitor is measured. Basic accuracy is 0.2 %. Ten ranges cover from 1pF to 199.9 milli-farads.
The 830 is available for $199.
Also see:
Preventing damage from transients
Locating AC leakage in industrial plants