The 555 timers I use don't always generate pulses

Thread starter David lopez
Start date May 12, 2019
Tags

electronics

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The discussion centers around issues with 555 timers not consistently generating pulses, with users suggesting possible causes and solutions. Key points include the importance of grounding pin 5 with a capacitor to reduce noise and ensuring that pin 4 is connected to Vcc. The original poster has tried different breadboards, noting that the circuit works on one but not the other, raising questions about potential wiring errors or contact issues. Participants emphasize the need for a circuit diagram and clear photos of the setup to diagnose the problem effectively. The conversation highlights the reliability of 555 timers despite the availability of modern alternatives.

May 16, 2019

Baluncore

Science Advisor

Those prototyping boards are susceptible to bent contacts. If a thick wire is used it can open the contacts, then when a thinner wire is used, that contact may be intermittent. Worn contacts may also be a problem as oxide forms on the base metal.

When a circuit does not work, test the contacts by inserting a long link in parallel with the suspect link, use different holes in the same bars.

Look under the board. It is usually possible to remove the base to access the connector bars, remove a bar, clean out the dirt, then carefully bend the spring contacts back into shape.