I've posted a complete solution for you on abse, under "Please suggest a time delay toggle switch [from sed]" , but since you can't get to the binary groups with google, I've also emailed it to you.
If you need a circuit description, ask and I'll post it here.
-- John Fields Professional Circuit Designer
John, I'd very much appreciate your design. That is certainly a professional design. In your circuit diagram, U3 is a dual oscillators for 33 and 45. U1 is for power on reset status. U2 AB is the time dealy switch. U2 CD is a toggle switch. U4 ensure there is only one clock signal will be pass to output. Am I right? Excellent. This circuit is very useful for me. Please forgive me raising some new issues. As I digging deeper, more questions is beuing raised. Both 33 and 45 ouput signals need to be adjusted to a certain level. Therefore, 33 and 45 clock signal has to be rectified and go through a variable pot .I found the original circuit has a output of 1V P to P rectified signal feed to the voltge follower. In this case, U4 gate may not be approriate.
John, Thanks for your patient in explaining the circuit. Just my curious, what is different between using IN4148 and 10K resistor connecting VCC to gate input.
--- No, U1 is the toggle. On power-up C5R2 resets it which disables the oscillators and sets the latch (U2C and D) to select the 33 RPM oscillator. Thereafter, a short press on the switch will enable the oscillators and send out the signal for 33RPM, and the next press will disable the oscillators and place the circuit in the power-up state. If a long press is made, the oscillators will be enabled but the 45 RPM signal will be output and, if the switch is pressed after that the oscillators will be disbled and the circuit will be returned to the power-up state. One thing I didn't put on the schematic but which you may want to consider doing would be to connect a high efficiency LED to U2-4, like this:
U2-4>---+ | [1k5] | [HLMP4700] |K GND>----+
What that will do is allow you to see when the circuit is ready to switch to 45, (when the LED lights up) and when you release the button after that the circuit will output the 45 RPM clock and the LED will go out.
---
--- No, U2CD is a latch used to select the 33 or 45 clock as the output.
---
--- The output from U4-11 will vary from about zero volts to Vcc, so it's already "rectified" in that it never goes below ground. If you need to attenuate the output, an easy way is to connect a pot from U4-11 to ground and to take the output from the wiper. If you need more current than CMOS can provide you can follow the output with an LM324 wired as a unity-gain buffer.
-- John Fields Professional Circuit Designer
-- The diodes isolate the gate inputs from each other when the switch is released.
Any time you need a (slow) circuit with more than one state, use a PIC or similar one-chip processor.
I put this off for years. When I finally bit the bullet and learned how to do a PIC, I haven't built a discrete circuit since. User interactions that can be nightmarish with hard logic become trivial with a processor.
You'll probably find that you didn't accurately specify your requirements. With a processor, it's easy to recover from those omissions. And the processor will probably take over 90% of the other associated stuff in your project. mike
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mingyan snipped-for-privacy@yahoo.com.hk wrote: > Absolutely correct. One button selection is really limited. However, > this application is only for my turntable. I can get used to it. i.e. > press the button to "On" 33. Press again, "Off". While play 33 want to > switch to 45. Turn it off, then press the button long enough to toggle > 45 oscillator.
So the OFF-to-ON requires a five second button press, and the ON-to-OFF does not, and successive OFF-to-ON's toggle the speed selection.
Your description is ambiguous, it could mean anything, but any one of the various opamp summer configurations will serve this purpose. You state elsewhere that the ultimate output should be a 1Vpp. It would help if you told us what power supplies and DC levels this circuit uses. View in a fixed-width font such as Courier.
. . . 12V . | . | . | . 12V _ _ |\\| . | | | | CLOCK1>--[22K]-+--------|+\\ . - - - | | >-+--+-->
. 0V CLOCK2>--[22K]-+ +-|-/ | | . |_ | |/| | | . |/| | | | | . ADJ 2.2K --> [5K] +------+ [1K] . /| | | . | | | . +----------+-----+ . | . --- . GND .
If you want just a single time delay then this works, the ON/OFF FF1 toggles 3.5 seconds after pressing the button, and the speed select FF2 toggles when the ON/OFF FF1 transitions from ON->OFF: View in a fixed-width font such as Courier.
. . . . +-----------+------------------------------> OFF TO . | FF1 | FF2 4066 RSTs . | ON/OFF | 33/45 . | | +-----------+ . | ----- | 1=OFF | ----- | . | | | | 0=ON | | | | . +--|D Q| | +-|D Q|---|-----> 33RPM . | | | | | | 4066 . | _| | | _| | RSTs . +-->CK Q|--+-------------->CK Q|---+-----> 45RPM . | | | | | . | | R/S | | R/S | . | ----- ----- . | | | . | - - . | GND GND . | . | . | . +-----------------------------------+ . | . Vdd | . | | . | | . +-----+ HEF4538B | . | | | . | | ---OS1--- | . |o | |__ | | . -| +------|I0 | | . |o | | Q| | 3 SECS . | | | | | - - . +------------|I1 | | | | . | | | _| | ____ . [10K] | | Q|--+ . | | |__ | . GND +------|CD | . | | | . [1M] | | . +------|RT CT|-+ . | | | | . | --------- | . | + | . +---------||-------+ . 3.3U TANTALUM . . . . DIODE OR OUTPUT TO 4066 RSTs AS INDICATED . . . . . Q,FF1 --|>|--+->33RPM RST Q,FF1 --|>|--+->45RPM RST . | 4066 | 4066 . | _ | . Q,FF2 --|>|--+ Q,FF2 --|>|--+ . | | . [10K] [10K] . | | . GND GND . . . . . . . . .
Fred Bloggs wrote:
You want the button to still be held or transition is disallowed- so that dual one-shot circuit must be modified like so: View in a fixed-width font such as Courier.
. . . . +-----------+------------------------------> OFF TO . | FF1 | FF2 4066 RSTs . | ON/OFF | 33/45 . | | +-----------+ . | ----- | 1=OFF | ----- | . | | | | 0=ON | | | | . +--|D Q| | +-|D Q|---|-----> 33RPM . | | | | | | 4066 . | _| | | _| | RSTs . +-->CK Q|--+-------------->CK Q|---+-----> 45RPM . | | | | | . | | R/S | | R/S | . | ----- ----- . | | | . | - - . | GND 100MS GND . | - - . | | | . | _ . +---------------------------------------------------+ . Vdd | . | | . +-------+--------------------------------+ | . | | | | . | +---|--------------------+ | | . | | | | | | . | | | ---OS1--- | | ---OS2--- | . |o | | |__ | | | |__ | | . -| | +------|I0 Q|----------------------|I0 | | . |o | | | | | | | Q| | . | | | | _| | | | | | . +---+----------|I1 Q| | +----|------|I1 | | . | | | | | | | | _| | . | | | | | | | | Q|-+ . | | |__ | | | | |__ | . | +------|CD | +-----------|------|CD | . | | | | | | | | . [10K] [1M] | | | 1M] | | . | +------|RT CT|-+ | +------|RT CT|-+ . | | | | | | | | | | . | | --------- | | | --------- | . | | + | | | | . | +---------||-------+ | +---------||-------+ . | 3.3U TANTALUM | 0.1U . +-----------------------------------+ . | . GND . . . DIODE OR OUTPUT TO 4066 RSTs AS INDICATED . . . Q,FF1 --|>|--+->33RPM RST Q,FF1 --|>|--+->45RPM RST . | 4066 | 4066 . | _ | . Q,FF2 --|>|--+ Q,FF2 --|>|--+ . | | . [10K] [10K] . | | . GND GND . . . . . . . . .
Fred Bloggs wrote:
Getting back to *my* original requirement that the circuit make a fast ON->OFF transition and a 3-second OFF->ON transition, one fairly low parts count mod that does this is shown below. The FF1 ON state disables OS1 from being triggered by the momentary switch by pulling OS1 /CD low. The addition of the Q1 network puts an ac-coupled trigger on OS2 I1 only when OS1 is not triggered. This means FF1 ON state allows the momentary to trigger OS2 for a 100ms switch debounce time and a fast turn-off. D2 bootstraps OS2 trigger so that switch bounce cannot truncate its pulse into CK of FF1. FF1 OFF state works like the original circuit since OS1 /Q is triggered low, the Q1 network has no effect on triggering OS2. View in a fixed-width font such as Courier.
. . . . +-----------+--------------------------------------> OFF TO . | FF1 | FF2 4066 RSTs . | ON/OFF | 33/45 . | | +-----------+ . | ----- | 1=OFF | ----- | . | | | | 0=ON | | | | . +--|D Q| | +-|D Q|---|-----> 33RPM . | | | | | | 4066 . | _| | | _| | RSTs . +-->CK Q|--+---------------------->CK Q|---+-----> 45RPM . | | | | | | . | | R/S | | | R/S | . | ----- | ----- . | | | | . | - | - . | GND | GND . | | . +---------------------------------------------------------------+ . | | . | | . Vdd | | . | | | . +-------+----------------------------------------+ | . | | | | | . | +---|----------------------+-------||--+->33RPM RST Q,FF1 --|>|--+->45RPM RST . | 4066 | 4066 . | _ | . Q,FF2 --|>|--+ Q,FF2 --|>|--+ . | | . [10K] [10K] . | | . GND GND . . .
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