74LS74N Datasheet, 74LS74N PDF, 74LS74N Data sheet, 74LS74N manual, 74LS74N pdf, 74LS74N, datenblatt, Electronics 74LS74N, alldatasheet, free. The SN54 / 74LS74A dual edge-triggered flip-flop utilizes Schottky TTL cir- cuitry to produce high speed D-type flip-flops. Each flip-flop has individual clear and. This device contains two independent positive-edge-trig- gered D flip-flops with complementary outputs. The infor- mation on the D input is accepted by the.

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I did the following: Feeling confident, I used a satasheet circuit to feed the clock pin3 with the same set up I had initially and got the led from Q1 to blink, then I did the same for the second half of thebut the clock2 pin11 being fed by Q’1 pin6.

Inputs can not float. Make sure by power you mean the positive side of a 5 volt DC source.

Try increasing the resistors to ohms or so. The traditional solution for switch inputs is to put the switch between the input pin and ground. Email Required, but never shown. I connected pin3 clock to ground through a 10k resistor in addition to having the push button from power. Like vatasheet for example:.

If you use too low of a voltage source, then the circuit will not operate. Note the pull up resistors at the datashwet of both NAND gates.

74LS74N Datasheet

Adding a 5K or so pull-up resistor is good practice, but usually not necessary. A 74LS74 has a nominal rating of 16 mA when low. Sign up using Email and Password. Is there a point where I may consider the chip is not functioning properly?


If using a switch to Vcc you need a pull down resistor say, 10K datzsheet to ground. The easiest fix but not the prettiest is to connect a capacitor across the button one leg of the capacitor to one button leg, and the other leg of the same capacitor to the other leg of the same button.

74LS74 Datasheet

This basically means the connections in the button open and close very fast more than you would like. Sign up or log in Sign up using Google.

Because of this, the clock is seeing multiple pulses when you intended on making only one. As it happens, you can do this cheaply by using the unused half of the chip as a SR flip-flop.

As WhatRoughBeast pointed out, you need to apply this practice to all inputs. It’s not bad for experimentation purposes, but if later on you decide to never use the set or clear operations of the chip, you could tie them directly to power. You need to de-bounce your switches in order to get predictable results.

Sign up using Facebook. CMOS parts 74ACxx, 74HCxx, and others with a “C” are CMOS and have very high impedance inputs – they can be used with high value pull-up or pull-down resistors – but ALL inputs must be connected somewhere, else they may be seen as “maybe” levels, and cause the chip to draw excessive current. I tried the arrangement you outlined.


Since the inputs source current, they must be pulled Low with a small under 1K resistance to be seen as a logic Low.

Better practice is to connect the switch between input and ground, to 74ld74n a solid Low when the switch is closed.

74LS74 Datasheet, PDF – Qdatasheet

There are quite a number of changes you need to make. Logic ICs should never have floating inputs. Including 74la74n inverse-clear and inverse-set for the half of the you are using. You can’t have floating inputs. Also, connect a resistor from the clock input pin 3 to ground.

The input of digital circuits needs to be either on or off. Is there a way to test it with a simpler configuration? I get the feeling that I connected something wrong initially.

I’ll amend my question to make it more clear. But instead of flipping from Q to Q’ when I push the button, it just blinks rapidly.

I tried unsuccessfully to make an SR flip flop out of it too. If using a switch to ground you need a pull up resistor again, say, 10K ohms to Vcc. To a circuit, this means switch is on, and switch is off and this happens at a faster than expected rate for a short time.