The logic probe can indicate four input states, as follows: floating inputâ€”all LEDs off..
The circuit uses a dual LED. When power is applied to the probe throughthe power leads, and the input is touched to a low level or ground, Ql is cut off. This will cause Q2 to conduct since the base is positive with respect to the emitter. With Ql cut off and Q2 conducting, the green diode of the dual LED will be forward biased, yielding a green output. Touching the probe tip to a high level will cause Ql and Q2 to complement, and the red diode will be forward biased,.....
These circuits illustrate some of the common logic functions..
An optoelectronics device is used to couple a digital (TTL) signal to another system. The photodiode in the optocoupler drives an LM311 set up to produce a TTL compatible output...
When the probe is in contact with a TTL low (0) the probe emits a low note. With a TTL high (1), a high note is emitted..
The low Rds and high peak current capability ofthe DG419 makes it ideal for discharging anÂ·integrator capacitor. A high logic input pulse disconnects the integrator from the analog input and discharges the capacitor. ..
Using this simple resistor circuit, you can trick your oscilloscope into displayin..
The logic pulser generates pulses at 500 Hz or 0.5 Hz. When the pulser`s.tip connects to an input that is already being driven high or low, the pulser senses thelogic state and automatically pulses the input..
This probe makes possible relative measurements of rf voltages to 200 MHz on a 20,000 ohms-per-volt multimeter..
Only the CD4009AE hex buffer, two resistors, and two LEDs are required for a logic probe. CMOS logic probe features 10120 input impedance and covers 3 to 15 V range. ..
An MFP102 FET is used as a wideband amplifier. LI can be 100 for 30 to 100 MHz or 1000 for 2 to 30 MHz. For LF, ..
Transistors Q1 and Q2 form a buffer, providing the probe with a reasonable input impedance. Q3 and Q4 form a level detecting circuit. As the voltage across the base-emitter junction of the Q3 rises above 0,6 V the transistor turns on thus turning on Q4 and lighting the red (high) LED. Q5 and Q6 perform the same function but for the green (low) LED. Ql, Q4, Q5 are all PNP general purpose silicon transistors (BC178 etc)..
This circuit is useful for monitoring slow logic pulses as a keying monitor or digital clock alarm. The Schmitt trigger is connected as an oscillator...
This simple circuit provides for level shifting from any logic function (such as MOS) operating from minus to ground supply to any logic level (such as TTL) operating from a plus to ground supply..
The compact test probe provides rapid "measurement" of voltage levels at digital gates, fuses, diodes, batteries, and ..
Â· This circuit is used for analog signal selection or time division multiplexing. As shown, the feedback signal places the selected amplifier channel in a voltage follower (noninverting unity gain) configuration, and provides very high input impedance and low output impedance. The single package replaces four input buffer amplifiers, four analog switches with decoding, and one output buffer amplifier. For low-level input signals, gain can be added to one or more.....
This logic probe uses a CD4009 CMOS hex inverter. The characteristic high-input impedance of CMOS gives the advantage..
The HA-4900 series comparators can be used as versatile logic interface devices, as shown in these circuits. Negati..
Gates Gl and G2 together with resistors Rl and R2 form a simple voltage monitor that has a trip point of 1 volts. Gate G3 is simply an inverter. The display section of the tester consists of a common anode alphanumeric LED and current-limiting resistors..
This circuit reconstructs and separates analog signals which have been time-division multiplexed. The conventional method, shown on the left, has several restrictions, particularly when a short dwell time and a long, accurate hold time is required. The capacitors must charge from a low-impedance source through the resistance and current-limiting characteristics of the multiplexer. When holding, the high-impedance lines are relatively long and subject to noise pickup.....
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