Hmm, or should I be using an "analogue switch" IC for this function?
I'd now like to understand if it is possible to use transistor circuit to switch between two different signals.
I'd now like to understand if it is possible to use transistor circuit to switch between two different signals.
Indeed it is possible. After all digital chips are made out of transistors I suggest you to skip transistor switch build, just learn multiplexers. Better invest your time into something more useful
https://en.wikipedia.org/wiki/Multiplexer
What you want is 2:1 SPDT switch (multiplexer), like http://www.ti.com/product/cd4053b that chip have 3 switches inside.
I'd now like to understand if it is possible to use transistor circuit to switch between two different signals.
Indeed it is possible. After all digital chips are made out of transistors I suggest you to skip transistor switch build, just learn multiplexers. Better invest your time into something more useful
https://en.wikipedia.org/wiki/Multiplexer
What you want is 2:1 SPDT switch (multiplexer), like http://www.ti.com/product/cd4053b that chip have 3 switches inside.Actually the 4053 is a single 1P8T switch (pick one of , fed from a 3-bit number
Where as the 4066 might be more useful (and easier to find). Four individual SPDT switches
http://www.ti.com/product/CD4066B
Actually the 4053 is a single 1P8T switch (pick one of , fed from a 3-bit number
Where as the 4066 might be more useful (and easier to find). Four individual SPDT switches
http://www.ti.com/product/CD4066B
If it's just one channel, then a quad NAND can be used. It will be slightly slower, than an analogue switch, but it has the advantage of being buffered.
If it's just one channel, then a quad NAND can be used. It will be slightly slower, than an analogue switch, but it has the advantage of being buffered.
If it's just one channel, then a quad NAND can be used. It will be slightly slower, than an analogue switch, but it has the advantage of being buffered.
Would you mind talking me through the operation of the circuit you showed here? It looks to me like the decision of which input is connected to the output will depend on the state (high/low) of the input signals.
In my relay circuit, the selection of which input signal is connected to the output is completely determined by the control pin.
Forgive my slow comprehension, this is why I'm always tempted to use relays - their operation is so simple !
I'd now like to understand if it is possible to use transistor circuit to switch between two different signals.
Indeed it is possible. After all digital chips are made out of transistors I suggest you to skip transistor switch build, just learn multiplexers. Better invest your time into something more useful
https://en.wikipedia.org/wiki/Multiplexer
What you want is 2:1 SPDT switch (multiplexer), like http://www.ti.com/product/cd4053b that chip have 3 switches inside.Actually the 4053 is a single 1P8T switch (pick one of , fed from a 3-bit number
Where as the 4066 might be more useful (and easier to find). Four individual SPDT switches
http://www.ti.com/product/CD4066BNo, '4053 is three SPDT switches.
Of course you're right. My bad is I looked at the datasheet for the 4051 (which was the original PDF referenced) which is a 3 to 8 1P8T switch and to make matters worse, I had a complete brain-fart thinking the 4066 was double throw. I'll stick to typing only when I'm awake. 4053 will work nicely, but I typically keep 4066s on hand, so I'd probably just glue a couple of channels together to make what the OP was talking about.
Hello,
I'd now like to understand if it is possible to use transistor circuit to switch between two different signals.
Specifically, I'd like to find a circuit which will perform the same function as my relay switching circuit below.
In this case, the MCU digital output state determines which signal from the inputs is connected to the output.
I'm amazed most people, including myself, missed that.
I'm amazed most people, including myself, missed that. Yes, it won't work. R2 will limit the current too much for the relay to turn on.
tron9000 thank-you for the clear explanation. My confusion was that I was thinking of the signals as analogue. CLearly this is a solution suitable for digital logic signals.
A reply from a beginner: My (simplified) version of yours to turn on the relay would look like this. The need of a base resistor could propbably be argued and you only have ~4.3V for the relay as opposed to 5V.
Edit: Assuming of course, the MCU output delivers enough current and is 5V as well, so you have 5Vb.