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  1. crutschow

    Alternating L/R 4-way flashers

    Well, you are welcome to do that, but then all the lights would go on at the same time (Look at the the relay coil connections. It is de-energized when the flasher output is 12V). I did that so the common SPST vehicle relay could be used. True. The turn lamps would likely be isolated but the...
  2. crutschow

    Alternating L/R 4-way flashers

    Okay, so here's my take on a circuit to do that using one relay and four diodes for isolation: The diagram shows a SPDT relay but you can use a standard SPST vehicle relay. When the flasher is off, the small coil current goes through the low resistance of the unlit incandescent bulbs to energize...
  3. crutschow

    Timer Circuit design needed... Help !!!

    Below is the LTspice sim of a circuit using two 555 timers to do what you want: U1 is configured as an astable multivibrator that generates a 10s ON, 1s Off signal to the motor power relay U4 (green trace), and U3 is configured as a toggle flip-flop to flip the motor-field reverse relay U2 at...
  4. crutschow

    Timer Circuit design needed... Help !!!

    How do you reverse this brushed AC motor? Reversing the connections on an AC motor has no effect on its rotation direction.
  5. crutschow

    Can an audio amplifier be used to transmit or receive radio signals?

    No, your are not understanding the "facts". You need to broadcast an audio signal by modulating an RF carrier frequency. Broadcasting the signal directly as a radio wave would likely result an a signal too weak to detect, unless you had a transmitting and receiving antenna the was very large...
  6. crutschow

    Speaker capabilities of consumer products

    Case of what? How quiet?
  7. crutschow

    Voltage regulator driving a pass transistor...

    The pre-regulator could be just an NPN BJT or N-MOSFET configured as a follower with a Zener reference from the base/gate to ground.
  8. crutschow

    Voltage regulator driving a pass transistor...

    Note that the bottom circuit has poorer regulation and temperature stability, since the Vbe voltage of the transistor is not is feedback loop.
  9. crutschow

    Speaker capabilities of consumer products

    Best would likely be to disconnect the internal speakers and connect some full(er) range external speakers with proper enclosures (e.g. bookshelf type). Otherwise, if you connected external speakers in parallel with the internal, you could overload the amps with too low an impedance. Adding an...
  10. crutschow

    Switching direction of a 12V motor with two push-to-make switches

    Glad to hear that it worked well.
  11. crutschow

    A question about "output stages".

    Post the schematic so we can know what you are referring to.
  12. crutschow

    Mixing output from 3 op amps

    Below is the LTspice sim of an example Baxandall bass and treble control circuit:
  13. crutschow

    Mixing output from 3 op amps

    Seems unlikely that the TS has any further interest in this year old thread.
  14. crutschow

    Switching direction of a 12V motor with two push-to-make switches

    You could use a 4-way DPDT light switch for that purpose. Note that you likely want to add 4 diodes across the switch contacts, similar to that shown in my post #15, to protect them from arcing due to the motor inductance.
  15. crutschow

    Switching direction of a 12V motor with two push-to-make switches

    Below is a simple circuit that should do what you want. It consists of a standard DPDT relay (not latching), two SPDT limit switches, and 5 diodes. The motor runs to the right with the relay de-energized as shown. When the Right Limit Sw is activated, the relay coil is energized, reversing the...
  16. crutschow

    Switching direction of a 12V motor with two push-to-make switches

    So the switches are controlled by the spider movement, not by a person pressing the switch? So the switch is really a limit-switch, not a push-to-make switch which, to me, implies someone "pushing" the switch.
  17. crutschow

    Switching direction of a 12V motor with two push-to-make switches

    I'm a little confused. What will the buttons do if the spider goes up and down the "web" by itself with the bistable relays? Or what is the expected sequence of operation using the buttons?
  18. crutschow

    How to eliminate 12V puck light LED flicker?

    Since the driver has a DC output, I don't understand why its flickering. Adding a large capacitor across the DC output (e.g. 1mF or larger) could help.
  19. crutschow

    I can't install a wireless door bell...

    Wouldn't one of these long-range wireless doorbells work for you? Several claim over a 1000' (300 meters) range, and one (not cheap) unit claims 4000', so should have enough signal power to go the distance plus through the house walls.
  20. crutschow

    maximum DC Voltage

    Yes, standard regulators do, but perhaps you are not familiar with the LDO type I suggested. Some of those can work down to much less than a volt. I have a discrete design that works down to the on-resistance drop of a MOSFET. So the "what then" is, as the input drops below the regulated...
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