Hi
I have seen this pot in ebay, of course by the price I dont believe that its an ALPS pot, but for the price ($13,54)... But I cant really understand how the channel selector works, unless another board with some relays is missing... I have asked the sellers but none could give me an proper answer, It seems they sell things and dont know how it works.
If the link doesnt work, just look in ebay for " 6ch Remote motor ALPS potentiometer control "...
Thanks
I have seen this pot in ebay, of course by the price I dont believe that its an ALPS pot, but for the price ($13,54)... But I cant really understand how the channel selector works, unless another board with some relays is missing... I have asked the sellers but none could give me an proper answer, It seems they sell things and dont know how it works.
If the link doesnt work, just look in ebay for " 6ch Remote motor ALPS potentiometer control "...
Thanks
Hi, I found some schematic for the potientometer board I bought, but it doesnt show the values of the resistors and which diode has to be used. Can anyone give me a hand?. What would be the values of R1, R2 and R3 that are the R for the led, the values of R4, R5 and R6 wich will be the R of the 8050 NPN transistor and wich diode it has to be use as D1, D2 and D3.
Thanks A lot!!!
Thanks A lot!!!
Attachments
For small relays a 1n4002 would do to absorb the back emf from the coil.
I have used 1n4048 and 1n914 without any problems.
The switching transistors must operate saturated. This requires the base current to be ~ relay coil current /10.
Size the base resistor to allow this high current to flow.
If your Vcc is <=30V and the relays do not require more than 30mA, then any To92 >=50Vceo and >100mA Ic continuous, will do for switching duty.
I have used 1n4048 and 1n914 without any problems.
The switching transistors must operate saturated. This requires the base current to be ~ relay coil current /10.
Size the base resistor to allow this high current to flow.
If your Vcc is <=30V and the relays do not require more than 30mA, then any To92 >=50Vceo and >100mA Ic continuous, will do for switching duty.
Measure the coil resistance.
Calculate the coil current using that 5Vcc.
Compare to datasheet current.
Expect about 40mA for a 5V coil.
The saturated transistor base current will need to be ~4mA (40mA/10).
The available voltage will be 5-0.8 = 4.2V Note that saturated Vbe is much higher than the usual ~600mVbe.
1k0 will pass 4.2mA if the relay signal voltage is 5V from zero source impedance.
If the source is not zero resistance, then the actual source resistance must be subtracted from the base resistor value, so that you achieve the coil current/10.
Calculate the coil current using that 5Vcc.
Compare to datasheet current.
Expect about 40mA for a 5V coil.
The saturated transistor base current will need to be ~4mA (40mA/10).
The available voltage will be 5-0.8 = 4.2V Note that saturated Vbe is much higher than the usual ~600mVbe.
1k0 will pass 4.2mA if the relay signal voltage is 5V from zero source impedance.
If the source is not zero resistance, then the actual source resistance must be subtracted from the base resistor value, so that you achieve the coil current/10.
Last edited:
- Status
- This old topic is closed. If you want to reopen this topic, contact a moderator using the "Report Post" button.