NL405 - Width/Delay

The NL405 is a digitally controlled pulse duration generator and is used to produce precise pulses of adjustable duration with high accuracy and repeatability.  This module combines many of the features of the discontinued NL401 Digital Width and NL403 Delay/Width into a single unit.

The NL405 produces TTL logic output pulses (of both polarities) that have a duration set using three decades of thumbwheels and a seven (7) position range switch. It also features a press to start button, LED indication of an output and a separate logic output signal at the end of the defined WIDTH time. It was designed as a replacement for the NL401 and, in most places where the NL403 would have been used.

NL501 - Logic Gate

The NL501 module contains two logic gates each with two inputs and complementary outputs. Both of these gates can be independently configured by PCB mounted switches as either 2-input AND gates or 2-input OR gates. The open circuited inputs are automatically held low for the OR function or high for the AND function and a further switch allows expansion of the second gate to take the output of the first as a third input. This enables a 4-input AND gate or a 4-input OR gate to be realized. A further possibility is a 3-input AND or OR gate where one of those inputs is a 2-input OR or AND function from the other gate. Provision is made for input 1 of gate 1 to be connected to the output of the module to the left and all 4 outputs are available for selection as the output to the module to the right. This is done by jumper plugs at the rear of the PCB.

NL505 - Flip Flop

The NL505 can be operated either as a "set-reset" flip-flop or as a "toggled" complementing flip-flop. This makes it useful in setting up conditional and "single-shot" stimuli, and testing logic outputs for the presence of pulses, logic levels etc.

It has three inputs, Set, Complement and Clear, and two outputs (Q and Q') all of which drive or are driven from TTL logic (ie +5V and 0V).  A LED indicator is illuminated when the Q output is at a high level.

NL603 - Counter

The NL603 Counter is a two-decade counter incorporating a display. It can function in three different modes to give counting, gating of an external pulse generator or division of an input frequency. The unit has a GATE input as well as a RESET to allow electrical control.

Multiple units may be combined for higher count or resolution.

NL730 - Pulse Shift

The NL730 contains a delay line consisting of a 500 bit shift register, with associated gating and clock logic. Logic pulse trains applied to the input emerge from the output after a delay which is set by the front panel rotary switches (Delays of 1.25, 2.5, 5.0 and 10 msec with a multiplier switch of x1, x10, x100 and x1000 giving a delay range of 1.25 msec to 10  secs).