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arivel1's Achievements


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  1. because they are not normal relays, but bistable single coil latches.
  2. i noticed a problem. when the opamp does not work its output is at zero volts, this state does not agree with the TC4420 because it contains logic gates whose outputs cannot be at zero but high or low. https://ww1.microchip.com/downloads/en/DeviceDoc/21419D.pdf so i think the only solution is to use push pull transistor or mosfet or darlington. do you confirm?
  3. Hello. I would like to make a volume attenuator composed of bistable single coil latch relays in logarithmic resistor ladder configuration. to do this I thought of using a binary counter 40193 whose outputs go to an operational amplifier. the function of the operational amplifier is to send a pulse to the TC4420 half-bridge mosfet (attention, only one pulse at each change of state of the 40193) which controls the relay coil. to drive the bistable latch relays it is customary to use a pulse in one direction or the other without leaving the coil under voltage all the time. as you can see from the attached image the other end of the coil is connected to the zero of the dual power supply. to simplify, only one component of each type appears in the image (opamp, tc4420, relay), but in the real circuit there are at least six. the problem is the following: which op amp should i use? and which configuration is the most suitable?
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