Logic probe
In this article we will explore the topic of Logic probe and its impact on today's society. Logic probe has been the subject of interest and debate for years, and its relevance has not diminished over time. In recent decades, we have seen significant advances and research around Logic probe, leading to greater understanding and awareness of its importance. Through this article, we will delve into the different aspects surrounding Logic probe, from its history and evolution to its influence in different areas of daily life. We hope that this exploration contributes to shedding light on Logic probe and its implications in today's world.
A logic probe is a low-cost hand-held test probe used for analyzing and troubleshooting the logical states (boolean 0 or 1) of a digital circuit. When many signals need to be observed or recorded simultaneously, a logic analyzer is used instead.
Overview
While most logic probes are powered by the circuit under test, some devices use batteries. They can be used on either TTL (transistor-transistor logic) or CMOS (complementary metal-oxide semiconductor) logic integrated circuit devices, such as 7400-series, 4000 series, and newer logic families that support similar voltages.
Most modern logic probes typically have one or more LEDs on the body of the probe:
- an LED to indicate a high (1) logic state.
- an LED to indicate a low (0) logic state.
- an LED to indicate changing back and forth between low and high states. The pulse-detecting electronics usually has a pulse-stretcher circuit so that even very short pulses become visible on the LED.
A control on the logic probe allows either the capture and storage of a single event or continuous running.
When the logic probe is either connected to an invalid logic level (a fault condition or a tri-stated output) or not connected at all, none of the LEDs light up.
Another control on the logic probe allow selection of either TTL or CMOS family logic. This is required as these families have different thresholds for the logic-high (VIH) and logic-low (VIL) circuit voltages.
Some logic probes have an audible tone, of which vary across models. A model may 1) emit a tone for high logic state otherwise no tone, or 2) emit a higher frequency tone for a high logic state, lower frequency tone for a low logic state, and no tone for no connection or tri-state. An oscillating signal causes the probe to alternate between high-state and low-state tones.
History
The logic probe was invented by Gary Gordon in 1968 while he was employed by Hewlett-Packard.[2][3]
References
- ^ Elenco LP-560 logic probe
- ^ "IC Logic Checkout Simplified" (PDF). HP Journal. No. 6. 1969. pp. 14–16.
- ^ US 3543154, "Logic Probe"
External links
