Royce thank you for your guidance. My 1st reaction was "well why didn't he just point me to a circuit?" However I did my own searches & seeing the huge variety between 1999 & 2023 both brushed & brushless I can see why you wud be hesitant to forward a single link. Many are Arduino-based, or pic, or some other complex whereas i was hoping for something no more complicated than building an AM broadcast radio. From several articles i finally understand how ESCs work (pwm) & for that matter what the receiver output signal looks like. So without even printing a schematic let alone building something I hav now learned what I had hoped to learn. Thanks to all here who hav contributed, this is a wonderful website especially for us Newbys.

Hi Dave we seem to have been through the same learning curves! I remember the little round servo chip in the Pompey cct, I put mine in a small tobacco tin and used the tin as a heat sink.
I lent it to a friend for his boat and he used it a lot then sold it to someone else! Goodbye ESC.

The relay switch, I think someone told me the idea, and I drew up a cct. The transistor that called the relay was across a resistor and when the resistor got to have 0.7 volts across it it set off the relay.
I used to enjoy those experimental days.

The last cct I put together, afterall you take a bit of this and a bit of that and join it all up! It was for the water level controller in a steam boiler for a model boat, all put together for a 24 hour endurance contest. That was in 1988, rather a while ago now! All published in Radio Control Model Boat builder, also gone now.

However there was a spin off from that cct as I developed it to work in a small steam supplier as used in bakeries and they sold into Safeways Supermarkets. I think Morrisons took them over but a long while ago now.

It seems that most things have been put together for you to buy now and as you say the components would cost you more than the finished article.

The BEC I used to make was a cct I found in the Model Cars magazine, still got it somewhere. The beauty of it was that it limited the i/p voltage to 0.7 volts plus the zennor diode value but it followed the voltage down rather than cutting off dead as does a one piece chip.

The last bit of electronics I bought was a DC Buck converter from Components shop. Works great
regards
Roy

Hi Roy
I like you made my own ESC's and Radio gear when the costs were beyond my means.
I do believe the transistor unit using 3055 and 2955 large metal transistors was called "Pompeii" and I used two in my four propped HMS Wolverton cruiser, one for each motor driving two props via a homemade gearbox. Needed a big heatsink as the voltage drop was high so they got hot.
The Electronize kit used a relay to change direction and had a built in BEC so much more efficient and as you say the MOSFET used had a low voltage drop so ran cool. Signetics no longer make the chips used but I acquired a strip of about 10 from a fellow modeller who was an ex employee who used to work for the company.
Interesting idea about using a relay at full power to avoid the voltage drop and heat. Must have seemed like an early Turbo powered boost when engaged.
BECs have evolved over the years and I have used the simple 7905 and also the more recent LM317 which I used to power all the leds in my RMS Olympic.
Nowadays you can buy kit that is probably cheaper than the parts needed so it's not surprising many choose that route. Hopefully RodC will find a suitable circuit to build and enjoy the learning curve.
Dave976

Hi Rod I used make my own esc's when they were relatively dear. Based around the early servo chip, forgotten its number now but no longer available. You said you wanted a fwd/rev brushed motor cct?

There are a number of circuits based on the 555 chip but these are not that stable and prone to interference.

Have you tried a search for a cct? After a few minutes I found several. I do not make them anymore too much strain on the eyesight.

I used to use high quality 16 amp contact relays for the reversing ccts and before that I used the big OC29 or 35, you needed 4 of them connected like an H with the motor connections across the middle.
However you lose 1.4 volts across each transistor pair and you need a heat sink.

The Electronize kit used the big transistors if I remember correctly and they were very good. I moved to these kits and made them up myself.

I have used FET's but only as part of a kit and with only a 0.1 volt drop across a FET no need for a heat sink.
I designed a simple additional cct. which depended on the current going through the o/p power transistor. It was a small transistor with emitter and base across a resistor.
When the the circuit was at max current the small transistor conducted and called a relay which switched the drive motor directly across the drive battery. This effectively disconnected the power transistors and saved on very hot heat sinks.

You may also need a BEC cct I can probably find a cct for this. It uses a zenor diode and a small power transistor. Probably all superceded now as my electronics stopped just before surface mounted compnents.

Good luck
Roy

I'm looking for a snow day project. I'm not fussy abt what someone wud send me to or direct me to. I'm not seeking any particular performance

Rod,
That is beyond my pay grade, but I will suggest that the high frequency brushed units I have received from Europe are a step above most others. Totally silent.

Brushed & brushless are obviously different topics. I'm interested in both

But right now I wud build the brushed type as I assume that it is simpler. Probably wud have much fewer parts as it's not controlling a 3-wire reversible motor.

And that's another thing, i want FWD/REV without a pause, so I need the rock crawler type, not the airplane sort.

Hi Rod
I too dabble in electronics and some years ago Electronize published the full circuit diagram for their brushed speed controller. Made my own printed circuit board and bought all the parts on line. Problem is it used a Signetics chip that is no longer available(709 or similar).
I have seen several circuits that use Pic chips but all are for brushed motors.
I suspect you are more interested in brushless controllers but let me know if you would like details of brushed controllers.
dave976