74HC Flip Flops are available at Mouser Electronics. Mouser offers inventory, pricing, & datasheets for 74HC Flip Flops. 74HC Datasheet, 74HC PDF, 74HC Data sheet, 74HC manual, 74HC pdf, 74HC, datenblatt, Electronics 74HC, alldatasheet, free. 74HC datasheet, 74HC circuit, 74HC data sheet: PHILIPS – Dual JK flip-flop with set and reset; positive-edge trigger,alldatasheet, datasheet.

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I’m trying to toggle the led forgot to add a resistor in the dafasheet, ah, also forgot to add a line from 5V to Vcc. Email Required, but never shown. By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Sign up or log in Sign up using Google. I’m using an SN74HC dual j-k” flip-flop chip. In this case, a ohm resistor, combined with the LED voltage and the limited high output drive of the flip-flop will give you about 6 or 7 mA LED current when on.

Maximum Low-Level input voltage with my Vcc at 5V is about 1. You need a de-bouncing circuit to feed the flip-flop’s clock input. Home Questions Tags Users Unanswered.

74HC Datasheet PDF – Philips Electronics

Caps are cheap and don’t take up much space, but the problems arising from not enough of them can be hard to diagnose. For more complex circuits using counters or state machines you can get the most amazing errors. And don’t think that you can ignore the inputs of an unused part of the circuit, such as the unused flip-flop in your 74HC LED does not light up, I’ve done something wrong again haven’t I?


LED lights up but does not toggle. Post Your Answer Discard By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy 74ch109 cookie policyand that your continued use of the website is subject to these policies.

(PDF) 74HC109 Datasheet download

John Honniball 2, 6 9. Just pull it down to 0V with a single resistor! I’m a complete amateur, I’ve probably gotten a million things wrong with this already.

In this case, it will show up as intermittent operation of the flip-flop, depending on whether or not it got daatasheet even or odd number of contacts when you press the switch. Just to show what I’m talking about, once you’ve got the circuit working, put an LED directly to ground on the flip-flop clock input, and watch what happens. Post as a guest Name. Always connect the GND pin.

Connect the cap directly to the sockets nearest the IC power and ground pins. Leaving unused pins floating particularly with CMOS can produce amazingly intermittent, bizarre and maddening errors.

Sometimes that works, and sometimes it doesn’t. On the one hand, it will try to draw too much current in the on state, and will datadheet clamp the output to a low voltage which the input will not recognize as high. As others have suggested, this could be a simple R-C network, or as a better option, use an SPDT change-over switch and a set-reset SR flip-flop as a de-bouncer. Sign up using Facebook. Don’t even think about it. Sign up using Email and Password. By clicking “Post Your Answer”, you acknowledge that you have read our updated terms of serviceprivacy policy and cookie policyand that your continued use of the website is subject to these policies.


A common way to do this is with cross-connected NAND gates. There are exceptions, with some circuits incorporating a built-in pull-up or pull-down resistor, but unless the data sheet mentions these, assume they don’t exist. You are clocking a flip-flop directly from a switch that has not been de-bounced. Please build the following circuit: Tie them all high or low.

Never leave it unconnected, datashedt if the circuit appears to work. When the circuit is powered, the led turns on but does not toggle when the momentary switch is pressed and released. WhatRoughBeast 49k 2 28