Neglected oscillator

[dbanner]

When the ICM7555 came on the scene, it was seen as the go-to multivibrator for low supply current operation (40-50uA). You see these chips especially in the typical PI front end Tx configured in the astable mode.

But what of the lowly 4047 low-power monostable/astable multivibrator? It has even lower current cosumption.
So why not use pin 13 to generate the audio and pin 10 to generate the square waves for the Tx drive?
So pin 10 output at say 400Hz which is a square wave triggered by 13, which is twice that amount at 800Hz. The 800Hz would be tapped for the audio.

Any thoughts on using the 4047 in a pulse design?

[Carl-NC]

I don't recall ever using a 4047 for anything so I can't speak to its qualities. The 555 can be set up with a pot to vary frequency, and another pot to vary pulse width. And can output either a positive pulse or a negative pulse, though not both at the same time. For creating the TX pulse, that's all you need. I think the 4047 astable cannot vary the pulse width, so it needs more logic. However, a micro can do everything.

[Andi68]

Ideal would be a device where frequency and pulse width can be set independently, e.g. the TL494

[dbanner]

The duty cycle in the 4047 cannot be adjusted, so there goes the whole hog. So for analog, it looks like the ubiquitous 555 is king.

[Carl-NC]

Ideal would be a device where frequency and pulse width can be set independently, e.g. the TL494

Another one I've never used.

The nice thing about the 555 is it is super-easy to get, and dirt cheap. Wiki says it's the most popular IC ever made, I believe it.

[dbanner]

Ideal would be a device where frequency and pulse width can be set independently, e.g. the TL494

I do see alot of these TL494/495 in power supply section of power amps for cars and the like which operate on 12Volts.