Yes. A CMOS inverter would require less power, but it may be insignificant. With the BJT, you can use large value resistors if you are running at 7Hz and you are wanting 10Meg impedance at your outputs.
Yes. A CMOS inverter would require less power, but it may be insignificant. With the BJT, you can use large value resistors if you are running at 7Hz and you are wanting 10Meg impedance at your outputs.
I also was going to use a 556 and run it for 20 minutes. So a CMOS chip and that would be 2 chips and save battery. Or throw out the 556 and use AVR Tiny uC to pulse it and go to sleep in 20 minutes. What are your thoughts on the uC over the timer. The code is already done. And I can blink an LED and have a switch for 2 settings.
Yes. A CMOS inverter would require less power, but it may be insignificant. With the BJT, you can use large value resistors if you are running at 7Hz and you are wanting 10Meg impedance at your outputs.
I also was going to use a 556 and run it for 20 minutes. So a CMOS chip and that would be 2 chips and save battery. Or throw out the 556 and use AVR Tiny uC to pulse it and go to sleep in 20 minutes. What are your thoughts on the uC over the timer. The code is already done. And I can blink an LED and have a switch for 2 settings.
If you have micro-controller experience, then it's simple enough to use a micro-controller. You can even use two output pins to give your bridged output directly (I modified a PIC magazine project like this, in order to give more power to a piezo beeper).
However, the output will be plus/minus the supply rail of the micro, which is normally only 5V?.
If you have micro-controller experience, then it's simple enough to use a micro-controller. You can even use two output pins to give your bridged output directly (I modified a PIC magazine project like this, in order to give more power to a piezo beeper).
However, the output will be plus/minus the supply rail of the micro, which is normally only 5V?.
Do you have this circuit on your website. I am very good with PIC and AVR, unfortunatly, it has caused me to be rusty now in analog design. There is a AVR Tiny of some type that is $.50. I was going to use that. it has 6 IO pins. One will select the Hz, one to blink the LED, and for sure 2 left to pulse. I am not sure one how I will hook the uC up and get plus and minus, but today I will write the code and dig out a breadboard. Can't I use LM7805 to run uC and then transistors to drive the plus minus off the 9V battery?
Do you have this circuit on your website. I am very good with PIC and AVR, unfortunatly, it has caused me to be rusty now in analog design. There is a AVR Tiny of some type that is $.50. I was going to use that. it has 6 IO pins. One will select the Hz, one to blink the LED, and for sure 2 left to pulse. I am not sure one how I will hook the uC up and get plus and minus, but today I will write the code and dig out a breadboard.
Ron H and Nigel, Thanks so much. Took 30 minutes of coding, and 15 to breadboard, and exactly what I wanted. That bridge thing works well. I get 10 volts p-to-p on the nose. Thanks again. in circuit is uC, 4 Rs, a switch, LED, battery. And poof.. Now to put it on my sore back...
Right now I have Pin1 and Pin2 two, and I pulse them alternatly and I get plus and minus 5volts out, I would like to be able to flip on the fly to switch off the plus 5 on the same two pins. Not sure if the bridge type pulsing will allow this. I guess I could switch VSS (that is ground one the battery) to one of the pin2 via a transistor, but that will make for a -5volts?
Right now I have Pin1 and Pin2 two, and I pulse them alternatly and I get plus and minus 5volts out, I would like to be able to flip on the fly to switch off the plus 5 on the same two pins. Not sure if the bridge type pulsing will allow this. I guess I could switch VSS (that is ground one the battery) to one of the pin2 via a transistor, but that will make for a -5volts?
Right, that was what I wanted to do, but was not sure if it would go negative.
I have Pin1 NEG and Pin2 POS, just stop pulsing Pin2.
Will try that tonight.
Right, that was what I wanted to do, but was not sure if it would go negative.
I have Pin1 NEG and Pin2 POS, just stop pulsing Pin2.
Will try that tonight.
Just stop pulsing Pin2, and set it HIGH, the other pin will then pulse negative with respect to Pin1. If you set Pin2 LOW, then Pin1 will pulse positive.